Venlafaxine (VF) and its active metabolite desvenlafaxine (DVF) are widely prescribed antidepressants that are only partially metabolized and excreted in significant amounts, making them clinically important analytes and environmentally relevant contaminants. In this study, a free-standing boron-doped diamond (BDD) electrode is exploited in a dual role for the electrochemical detection and degradation of VF and DVF, integrated into a custom 3D-printed dual-function electrochemical cell. The nucleation (BDD_NS) and growth (BDD_GS) sides of the BDD plate were systematically compared under different surface terminations. Oxidized BDD_NS (O-BDD_NS) provided three well-resolved oxidation peaks for VF, whereas hydrogen-terminated BDD_NS (H-BDD_NS) yielded a single distinct peak for DVF in 0.1 M H₂SO₄. Differential pulse voltammetric (DPV) methods were developed with limits of detection of 0.35 µM for VF (peak 1) and 0.34 µM for DVF and wide linear ranges in the low-to-high micromolar region. By exploiting the different surface-termination preferences and multi-peak behaviour of VF, simultaneous determination of VF and DVF was achieved. The methods showed good selectivity toward common interferents and were successfully applied to spiked river water and pharmaceutical capsules using the standard addition approach, giving recoveries close to 100 %. In the 3D-printed cell, BDD_GS was used for electrochemical advanced oxidation, achieving ∼97 % degradation of 1 mM VF and DVF in 0.1 M H₂SO₄ within 20 min under galvanostatic conditions, following pseudo-first-order kinetics. In situ DPV on BDD_NS enabled real-time monitoring of VF decay, demonstrating an integrated detect-and-degrade platform based on BDD and additive manufacturing.

Diamond's unique combination of hardness, high thermal conductivity, chemical inertness, and biocompatibility makes it a highly attractive material for next-generation technologies. However, its integration into functional devices has long been limited by the difficulties of processing bulk diamond. Recent advances in additive manufacturing have enabled the use of diamond in nano- and microparticulate forms, significantly expanding its accessibility and versatility. This review presents the state-of-the-art in printing with diamond particles using inkjet, screen, microcontact, and 3D printing techniques, which offer enhanced design freedom, compatibility with diverse substrates, and streamlined prototyping workflows. Particular emphasis is placed on how particle properties, together with ink, resin, filament, or powder formulation, influence print quality and final performance. The reviewed applications span microfabricated structures, various sensing, and thermal management devices, wear-resistant tools, and biomedical interfaces. Key technical challenges, including particle dispersion, interfacial bonding, and equipment wear, are addressed alongside emerging strategies such as surface functionalization, AI-assisted process optimization, and multimaterial integration. By bridging materials science and device engineering, printed diamond technologies offer a scalable and flexible route to high-performance, multifunctional components. This review serves as a resource for researchers aiming to integrate diamond into advanced printed material platforms.

Oil palm empty fruit bunch (OPEFB) is an abundant organic waste in Malaysia that is often disposed of through field burning. A previous study has shown that solar-driven steam gasification of OPEFB can produce hydrogen-rich syngas with an energy upgrade factor of 1.2 and a carbon conversion efficiency of 95.1 %. Beyond its potential as a biofuel, OPEFB can also act as a carbon sink, capturing photosynthetically stored carbon. This study explores the potential of amplifying OPEFB's negative carbon emissions through solar-driven gasification, using CO₂ as the gasifying agent. In this work, a Central Composite Design (CCD) approach was employed to assess the influence of temperature (1100–1300 °C) and CO₂/OPEFB molar ratio (1.6–3.0) on H₂/CO molar ratio and energy upgrade factor, with a constant OPEFB flow rate of 1.8 g/min. The results demonstrated that at an energy upgrade factor of 1.4, 94.9 % of the total carbon was converted into syngas with a H₂/CO molar ratio of 0.3. The maximum observed net carbon capture yield of 0.4 g C/g OPEFB was achieved at 1300 °C and a CO₂/OPEFB molar ratio of 3.0. The remaining carbon (94.4–95.7 wt %) was converted into biochar with low heavy metal content, which has potential as a soil enhancer.

Electrochemical wastewater treatment is a promising technique to remove recalcitrant pollutants from wastewater. However, the complexity of elucidating the underlying degradation mechanisms hinders its optimisation not only from a techno-economic perspective, as it is desirable to maximise removal efficiencies at low energy and chemical requirements, but also in environmental terms, as the generation of toxic by-products is an ongoing challenge. In this work, we propose a novel combined experimental and computational approach to (i) estimate the contribution of radical and non-radical mechanisms as well as their synergistic effects during electrochemical oxidation and (ii) identify the optimal conditions that promote specific degradation pathways. As a case study, the distribution of the degradation mechanisms involved in the removal of benzoic acid (BA) via boron-doped diamond (BDD) anodes was elucidated and analysed as a function of several operating parameters, i.e., the initial sulfate and nitrate content of the wastewater and the current applied. Subsequently, a multivariate optimisation study was conducted, where the influence of the electrode nature was investigated for two commercial BDD electrodes and a customised silver-decorated BDD electrode. Optimal conditions were identified for each degradation mechanism as well as for the overall BA degradation rate constant. BDD selection was found to be the most influential factor favouring any mechanism (i.e., 52-85% contribution), given that properties such as its boron doping and the presence of electrodeposited silver could dramatically affect the reactions taking place. In particular, decorating the BDD surface with silver microparticles significantly enhanced BA degradation via sulfate radicals, whereas direct oxidation, reactive oxygen species and radical synergistic effects were promoted when using a commercial BDD material with higher boron content and on a silicon substrate. Consequently, by simplifying the identification and quantification of underlying mechanisms, our approach facilitates the elucidation of the most suitable degradation route for a given electrochemical wastewater treatment together with its optimal operating conditions.

This study assessed the photoactivity of amorphous and crystalline TiO₂ nanotube arrays (TNA) films in gas phase CO₂ reduction. The TNA photocatalysts were fabricated by titanium anodization and submitted to an annealing treatment for crystallization and/or cathodic reduction to introduce Ti³⁺ and oxygen vacancies into the TiO₂ structure. The cathodic reduction demonstrated a significant effect on the generated photocurrent. The photoactivity of the four TNA catalysts in CO₂ reduction with water vapor was evaluated under UV irradiation for 3 h, where CH₄ and H₂ were detected as products. The annealed sample exhibited the best performance towards methane with a production rate of 78 μmol g_cat⁻¹ h⁻¹, followed by the amorphous film, which also exhibited an impressive formation rate of 64 μmol g_cat⁻¹ h⁻¹. The amorphous and reduced-amorphous films exhibited outstanding photoactivity regarding H₂ production (142 and 144 μmol g_cat⁻¹ h⁻¹, respectively). The annealed catalyst also revealed a good performance for H₂ production (132 μmol g_cat⁻¹ h⁻¹) and high stability up to five reaction cycles. Molecular dynamic simulations demonstrated the changes in the band structure by introducing oxygen vacancies. The topics covered in this study contribute to the Sustainable Development Goals (SDG), involving affordable and clean energy (SDG#7) and industry, innovation, and infrastructure (SDG#9).

In this work, we pioneered the preparation of diamond-containing flexible electrodes using 3D printing technology. The herein developed procedure involves a unique integration of boron-doped diamond (BDD) microparticles and multi-walled carbon nanotubes (CNTs) within a flexible polymer, thermoplastic polyurethane (TPU). Initially, the process for the preparation of homogeneous filaments with optimal printability was addressed, leading to the development of two TPU/CNT/BDD composite electrodes with different CNT:BDD weight ratios (1:1 and 1:2), which were benchmarked against a TPU/CNT electrode. Scanning electron microscopy revealed a uniform distribution of conductive fillers within the composite materials with no signs of clustering or aggregation. Notably, increasing the proportion of BDD particles led to a 10-fold improvement in conductivity, from 0.12 S m^-1 for TPU/CNT to 1.2 S m^-1 for TPU/CNT/BDD (1:2). Cyclic voltammetry of the inorganic redox markers, [Ru(NH₃)₆]^3+/2+ and [Fe(CN)₆]^3-/4-, also revealed a reduction in peak-to-peak separation (ΔE_p) with a higher BDD content, indicating enhanced electron transfer kinetics. This was further confirmed by the highest apparent heterogeneous electron transfer rate constants (k⁰_app) of 1 × 10^-3 cm s^-1 obtained for both markers for the TPU/CNT/BDD (1:2) electrode. Additionally, the functionality of the flexible TPU/CNT/BDD electrodes was successfully validated by the electrochemical detection of dopamine, a complex organic molecule, at millimolar concentrations by using differential pulse voltammetry. This proof-of-concept may accelerate development of highly desirable diamond-based flexible devices with customizable geometries and dimensions and pave the way for various applications where flexibility is mandated, such as neuroscience, biomedical fields, health, and food monitoring.

The ongoing challenge of water pollution by contaminants of emerging concern calls for more effective wastewater treatment to prevent harmful side effects to the environment and human health. To this end, this study explored for the first time the implementation of single-crystal boron-doped diamond (BDD) anodes in electrochemical wastewater treatment, which stand out from the conventional polycrystalline BDD morphologies widely reported in the literature. The single-crystal BDD presented a pure diamond (sp³) content, whereas the three other investigated polycrystalline BDD electrodes displayed various properties in terms of boron doping, sp³/sp² content, microstructure, and roughness. The effects of other process conditions, such as applied current density and anolyte concentration, were simultaneously investigated using carbamazepine (CBZ) as a representative target pollutant. The Taguchi method was applied to elucidate the optimal operating conditions that maximised either (i) the CBZ degradation rate constant (enhanced through hydroxyl radicals (^•OH)) or (ii) the proportion of sulfate radicals (SO₄^•−) with respect to ^•OH. The results showed that the single-crystal BDD significantly promoted ^•OH formation but also that the interactions between boron doping, current density and anolyte concentration determined the underlying degradation mechanisms. Therefore, this study demonstrated that characterising the BDD material and understanding its interactions with other process operating conditions prior to degradation experiments is a crucial step to attain the optimisation of any wastewater treatment application.

In this work, four different techniques were concurrently applied to study the interplay between local electroactivity and electrode surface characteristics of free-standing, polycrystalline boron-doped diamond (BDD). Scanning electron microscopy, electron back-scatter diffraction, Raman mapping and scanning electrochemical microscopy were used to probe the electrode morphology, grain orientation and boundaries, composition, and local electrochemical activity, respectively. Both nucleation and growth BDD surfaces together with the cross-section area were carefully investigated for the first time in a single study using the combination of all four techniques. This enabled us to obtain significant insights into the highly heterogeneous nature of the polycrystalline BDD material. Notably, boron dopants were confirmed to be non-uniformly distributed over the BDD material, which is characterized by a distinct columnar structure and composition of grains of various orientations. Particularly, the highest electrochemical activity was recorded on the highest doped (111) crystal orientation. In contrast, the averagely boron-doped (100)-oriented facet showed non-conductive nature. This highlights that the local electrochemical activity of the BDD surface is strongly grain-dependent and the most significant factors governing the obtained responses are crystallographic orientation and boron doping. Moreover, increased boron and sp² carbon content in the boundary regions was recognized by Raman mapping. However, such localized enrichment in impurities did not translate into enhanced electrochemical activity, which implies that boron atoms at the inter-grain areas are predominantly inactive. Finally, it is crucial to consider all characteristics of the polycrystalline BDD including crystal orientation, which is particularly relevant if micro- and nanoscale probing is intended.

The challenge of doping synthetic diamond with phosphorus stems from the atomic size mismatch between phosphorus and carbon atoms, which previously hindered achieving high phosphorus doping levels. This limitation delayed the exploration of phosphorus-doped diamond (PDD) in electrochemical applications, where it holds potential as a novel and appealing electrode material because PDD uniquely combines diamond's exceptional properties with phosphorus atoms inducing n-type conductivity. In this study, heavily doped PDD electrodes were successfully developed using chemical vapour deposition, followed by comprehensive microstructural and electrochemical characterisations. The influence of phosphorus doping, manipulated via high phosphine gas concentration or time-dependant precursor gas flow control, on the PDD properties was thoroughly examined. PDD layers grown at higher phosphine concentrations demonstrated enhanced phosphorus incorporation, leading to a higher prevalence of fine nano-crystalline diamond grains and non-diamond carbon components, while also slowing the growth rate. Notably, a distinct PDD sample produced under dynamic gas flow with lower phosphine concentration revealed larger grain sizes, increased effective deposition rate, and improved phosphorus levels compared to its counterpart synthesized under static conditions. Cyclic voltammetry in a 1 mol L⁻¹ KCl solution revealed a low double-layer capacitance (<11 µF cm⁻²) in all as-grown PDD electrodes. However, significant differences between the samples emerged during the experiments conducted with redox probes [Ru(NH₃)₆]^3+/2+ and [Fe(CN)₆]^3−/4−. Particularly, higher phosphorus content promoted well-developed voltammograms, significantly reduced peak-to-peak separation values, faster electron transfer rates, and increased peak currents. Furthermore, the possibility of using heavily P-doped diamond electrodes for the detection of two organic analytes, dopamine and ascorbic acid, was successfully manifested. All in all, the as-grown, highly P-doped diamond electrodes proved their ability, first time ever, to record well-defined signals of both inorganic redox probes and complex organic compounds, unravelling their potential in electroanalysis and sensor development and broadening the scope of PDD utilisation.

Fabrication of patterned boron-doped diamond (BDD) in an inexpensive and straightforward way is required for a variety of practical applications, including the development of BDD-based electrochemical sensors. This work describes a simplified and novel bottom-up fabrication approach for BDD-based three-electrode sensor chips utilizing direct inkjet printing of diamond nanoparticles on silicon-based substrates. The whole seeding process, accomplished by a commercial research inkjet printer with piezo-driven drop-on-demand printheads, was systematically examined. Optimized and continuous inkjet-printed features were obtained with glycerol-based diamond ink (0.4% vol/wt), silicon substrates pretreated by exposure to oxygen plasma and subsequently to air, and applying a dot density of 750 drops (volume 9 pL) per inch. Next, the dried micropatterned substrate was subjected to a chemical vapor deposition step to grow uniform thin-film BDD, which satisfied the function of both working and counter electrodes. Silver was inkjet-printed to complete the sensor chip with a reference electrode. Scanning electron micrographs showed a closed BDD layer with a typical polycrystalline structure and sharp and well-defined edges. Very good homogeneity in diamond layer composition and a high boron content (∼2 × 10²¹ atoms cm^-3) was confirmed by Raman spectroscopy. Important electrochemical characteristics, including the width of the potential window (2.5 V) and double-layer capacitance (27 μF cm^-2), were evaluated by cyclic voltammetry. Fast electron transfer kinetics was recognized for the [Ru(NH₃)₆]^3+/2+ redox marker due to the high doping level, while somewhat hindered kinetics was observed for the surface-sensitive [Fe(CN)₆]^3-/4- probe. Furthermore, the ability to electrochemically detect organic compounds of different structural motifs, such as glucose, ascorbic acid, uric acid, tyrosine, and dopamine, was successfully verified and compared with commercially available screen-printed BDD electrodes. The newly developed chip-based manufacture method enables the rapid prototyping of different small-scale electrode designs and BDD microstructures, which can lead to enhanced sensor performance with capability of repeated use.

This study presents environmentally friendly and low-cost synthetic routes to produce antimicrobial coatings over 5052 Al alloy based on plasma electrolytic oxidation (PEO) technology. Two methodologies were explored: the decoration with copper and anodic doping with copper ions. The porous oxide layers produced in silicate media presented two porous layers consisting of γ-Al₂O₃ crystalline phase and amorphous phases of aluminosilicate, silica, and Al(OH)₃. Small amounts of copper (<0.3 at.%) were detected in the PEO films. In the Cu-decorated film, copper clusters composed of Cu⁰ and Cu²⁺ species were observed visually as small black dots on the surface. In the Cu-doped film, the Cu²⁺ and Cu⁺ species were homogeneously distributed on the surface. The copper content affected the corrosion performance in aggressive corrosive media. The PEO coatings showed a remarkable antimicrobial activity after 24 h in standard tests. The antimicrobial effectiveness of the Cu-decorated sample was higher against S. aureus, while the Cu-doped sample was more effective against E. coli. The results demonstrated that differences in the PEO coating architecture can affect the material composition and, consequently, the bacterial inactivation mechanism. These findings can serve as a guide to tailor aluminum alloys for specific antimicrobial surfaces.

Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed laser irradiation (100 fs duration, 800 nm wavelength, 1.44 J cm⁻² single pulse fluence) to analyse the evolution of induced alterations on the surface morphology and structural properties. The aim was to identify the occurrence of laser-induced periodic surface structures (LIPSS) as a function of the number of pulses released on the unit area. Micro-Raman spectroscopy pointed out an increase in the graphite surface content of the films following the laser irradiation due to the formation of ordered carbon sites with respect to the pristine sample. SEM and AFM surface morphology studies allowed the determination of two different types of surface patterning: narrow but highly irregular ripples without a definite spatial periodicity or long-range order for irradiations with relatively low accumulated fluences (<14.4 J cm⁻²) and coarse but highly regular LIPSS with a spatial periodicity of approximately 630 nm ± 30 nm for higher fluences up to 230.4 J cm⁻².

In this work, three distinct heteroepitaxial single-crystal boron-doped diamond (SC-BDD) electrodes were fabricated and subjected to detailed surface analysis and electrochemical characterization. Specifically, the heteroepitaxy approach allowed to synthesize large-area (1 cm²) and heavily-doped (100)-oriented SC-BDD electrodes. Their single-crystal nature and crystal orientation were confirmed by X-ray diffraction, while scanning electron and atomic force microscopies revealed marked variations in surface morphology resulting from their growth on respective on-axis and off-axis substrates. Further, absence of sp² impurities along with heavy boron doping (>10²¹ cm⁻³) was demonstrated by Raman spectroscopy and Mott-Schottky analysis, respectively. Cyclic voltammetry (CV) in a 0.1 M KNO₃ solution revealed wide potential windows (∼3.3 V) and low double-layer capacitance (<4 μF cm⁻²) of the SC-BDD electrodes. Their highly conductive, ‘metal-like’ nature was confirmed by CV with [Ru(NH₃)₆]^3+/2+ probe manifesting near-reversible redox response with ΔE_p approaching 0.059 V. The same probe was used to record scanning electrochemical micrographs, which clearly demonstrated homogeneously distributed electrochemical activity of the heteroepitaxial SC-BDD electrodes. Minor differences in their electrochemical performance, presumably resulting from the somewhat different morphological features, were only unveiled during CV with surface sensitive compounds [Fe(CN)₆]^3−/4− and dopamine. The latter was also used to show the possibility of applying herein developed heteroepitaxial SC-BDD electrodes for electrochemical sensing, whereas experiments with anthraquinone-2,6-disulfonate revealed their enhanced resistance to fouling. All in all, heteroepitaxial SC-BDD represents a highly attractive electrode material which can, owing to the fabrication strategy, easily overcome size limitation, currently preventing broader use of single crystal diamond electrodes in electrochemical applications.

In this work, non-modified boron-doped diamond (BDD) was employed first time ever as the sensing material for the in-depth voltammetric study of the antiretroviral drug nevirapine (NVP) used to treat HIV infections. Two types of electrode surface pre-treatments, anodic oxidation and alumina-polishing, yielded BDD of different surface chemistry, denoted as O-BDD and p-BDD, respectively. Induced alterations in BDD surface composition reflected in distinct voltammetric responses of NVP, also dependant on the pH of the medium. The electrochemical oxidation of NVP on both electrodes, whose mechanism is proposed herein, has an irreversible character and is controlled by diffusion. The analytical figures of merit were assessed in a pH 2.0 buffer on O-BDD, and in supporting electrolytes of pH 5.0 and 13.0 on p-BDD using differential pulse voltammetry. Overall, NVP provided signals of excellent intra- and inter-day repeatability (RSD ≤ 5.0%) which remained unaffected even in the presence of common interfering compounds (e.g., glucose, ascorbic acid, uric acid, and dopamine). Even though the O-BDD electrode outperformed the p-BDD electrode in terms of sensitivity and the lowest detection limit achieved (0.04 μM), both O-BDD and p-BDD provided highly favourable analytical parameters fulfilling the requirements for clinical application for NVP sensing and monitoring in biofluids. This was also proved by electroanalysis of NVP in synthetic serum samples where recovery values between 96.3 and 103.0% were successfully achieved. Finally, unique properties of BDD allowed to develop a direct, modification-free, and reliable protocol for NVP detection, which paves the way for the full sensor development.

Black liquor (BL) is a highly alkaline byproduct from pulp mills. BL is rich in inorganic and organic compounds, with lignin (a natural polymer) being the most abundant. Following a waste biorefinery concept, the electrolysis of BL comprises lignin oxidation at the anode and hydrogen evolution at the cathode. These paired electrochemical processes show the promise to be carried out at lower cell voltage than that used in conventional alkaline water electrolyzers. Presently, new materials are required to improve the kinetics of the anodic reaction in the BL electrolyzer. Boron-doped diamond (BDD) can oxidize organic compounds at low overpotentials, making it a potential electrode material for BL oxidation. Herein, a BDD/Si electrode was produced, characterized by Raman spectroscopy and SEM, and employed for the oxidation of BL. The properties of the used kraft BL were determined, namely the pH (12.7), conductivity (470 mS cm⁻¹), organic/inorganic ratio (1.0), and Klason lignin content (42.2 g L^-1). Fourier-transform infrared spectroscopy was also used in the BL characterization. The BDD performance for BL oxidation was assessed by cyclic voltammetry, chronopotentiometry, and chronoamperometry. A number of exchanged electrons and a charge transfer coefficient of 3.0 and 0.8, respectively, were calculated. It was demonstrated that BDD presents a good activity for BL oxidation, comparable to that of platinum.

In this paper, the effect of boron doping on the electrical, morphological and structural properties of free-standing nanocrystalline diamond sheets (thickness ~ 1 μm) was investigated. For this purpose, we used diamond films delaminated from a mirror-polished tantalum substrate following a microwave plasma-assisted chemical vapor deposition process, each grown with a different [B]/[C] ratio (up to 20,000 ppm) in the gas phase. The developed boron-doped diamond (BDD) films are a promising semiconducting material for sensing and high-power electronic devices due to band gap engineering and thermal management feasibility. The increased boron concentration in the gas phase induces a decrease in the average grain size, consequently resulting in lower surface roughness. The BDD sheets grown with [B]/[C] of 20,000 ppm reveal the metallic conductivity while the lower doped samples show p-type semiconductor character. The charge transport at room temperature is dominated by the thermally activated nearest-neighbor hopping between boron acceptors through impurity band conduction. At low temperatures (<300 K), the Arrhenius plot shows a non-linear temperature dependence of the logarithmic conductance pointing towards a crossover towards variable range hopping. The activation energy at high temperatures obtained for lowly-doped sheets is smaller than for nanocrystalline diamond bonded to silicon, while for highly-doped material it is similar. Developed sheets were utilized to fabricate two types of diamond-on-graphene heterojunctions, where boron doping is the key factor for tuning the shape of the current-voltage characteristics. The graphene heterojunction with the low boron concentration diamond sheet resembles a Schottky junction behavior, while an almost Ohmic contact response is recorded with the highly doped BDD sheet of metallic conductivity. The free-standing diamond sheets allow for integration with temperature-sensitive interfaces (i.e. 2D materials or polymers) and pave the way towards flexible electronics devices.

High-entropy alloys (HEAs) have rapidly become one of the hottest research topics in several fields, including materials science, corrosion technology, and catalysis because of their multiple advantages and their potential applications. In this study, using a novel straightforward electroless deposition method, multi-elemental alloys (FeCoNiCuZn) supported on graphite were prepared with controlled metal loading (HEA/g-X; X = 40, 80, 100) without any high temperature post-treatments. These materials were characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, and showed a composition ranging from 11 at.% to 31 at.% for each metallic element, a total metal loading varying from 1.3 to 5.2 at.% (5.9 to 21.5 wt.%), homogeneous distribution, and an amorphous structure. Electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and chronoamperometry were used to evaluate the surface dynamics and the effect of the solution pH during the electrochemical hydrogenation of nitrobenzene using the HEA/g-40 material. The nitrobenzene conversion (>9 mmol_NB g_cat-¹ h⁻¹) and aniline production (≈ 4 mmol_AN g_cat-¹ h⁻¹) rates in Na₂SO₄ solution (at −1.0 V vs. Ag/AgCl) demonstrated a strong dependence on the applied potential. After comparing the results in alkaline medium (KOH), a competitive adsorption of species (nitrobenzene and H₂O) was observed, showing a synergistic effect that greatly improved the selectivity of the nitrobenzene hydrogenation to aniline, from 23% in Na₂SO₄ to an outstanding 94% in KOH at the same applied potential, surpassing the results of a platinum electrode (34% in KOH). These results provide insightful information regarding the nature of the active sites involved in each step of the reaction mechanism, and gives useful means to develop new, tailored multifunctional HEA electrocatalyst materials.

GenX is the trade name of the ammonium salt of hexafluoropropylene oxide dimer acid (HFPO-DA) and is used as a replacement for the banned perfluorooctanoic acid (PFOA). However, recent studies have found GenX to be more toxic than PFOA. This work deals with the electrochemical degradation of HFPO-DA using boron-doped diamond anodes. For the first time, an experimental study was conducted to investigate the influence of sulfate concentration and other operating parameters on HFPO-DA degradation. Results demonstrated that sulfate radicals were ineffective in HFPO-DA degradation due to steric hindrance by –CF₃ branch. Direct electron transfer was found as the rate-determining step. By comparing degradation of HFPO-DA with that of PFOA, it was observed that the steric hindrance by –CF₃ branch in HFPO-DA decreased the rate of electron transfer from the carboxyl head group even though its defluorination rate was faster. Conclusively, a degradation pathway is proposed in which HFPO-DA mineralizes to CO₂ and Fˉ via formation of three intermediates.

Boron-doped diamond (BDD) is of increasing interest for applications in electrochemical sensing. It is well known that the sp² carbon content in BDD influences its electrochemical properties as electrode material. In this work, evidence is provided that the surface sp² carbon content plays a crucial role in the electrochemical sensitivity of BDD towards glucose. Single-crystal BDD, freestanding polycrystalline BDD and glassy carbon (sp² carbon reference material) were examined by voltammetry. Neither single-crystal BDD, which is free of sp² carbon, nor pure sp² glassy carbon could detect glucose in the range of 0.2–1.0 V. On the other hand, glucose oxidation was observed on polycrystalline BDD, and with increasing intensity with increase of sp² carbon content. Thus, an optimum amount of (B-doped) sp² carbon in the BDD electrode is needed for best sensing performance. Understanding this, and being able to control the composition of BDD, are not only important to glucose detection but to any electrochemical sensing application involving BDD.