Electrochemical CO₂ reduction is emerging as a compelling route for renewable energy storage and carbon neutrality. Focus on improving catalyst selectivity and energy efficiency resulted in a surge of catalysis-centered research. The advent of artificial intelligence and high-throughput screening enables parallelized catalyst characterization to accelerate discovery, but their implementation into application-relevant device configurations is challenging. We present a scalable, high-throughput platform based on infrared thermography that preserves realistic electrochemical environments from lab to industrially relevant scales. We demonstrate the spatial and electrochemical homogeneity of a 16-well parallel electrolyzer and validate a combinatorial testing approach using copper-based catalysts with varied loadings and precursor chemistries. The results highlight how activity trends can be rapidly mapped under controlled conditions, while also revealing the limitations of activity-only combinatorial testing, particularly for multiproduct electrochemical applications in complex environments like CO₂ electrolysis on Cu. This platform thus provides an efficient pre-screening tool to accelerate catalyst discovery when analyzed appropriately and paired with follow-up single catalyst testing.

Catalyst lifetime is a primary technical bottleneck obstructing Cu-based CO₂ reduction (CO₂R), with restructuring via dissolution-redeposition being a commonly reported reason for selectivity loss. Here we examine how atomistic restructuring manifests at the microlevel of gas diffusion electrode (GDE)-based systems, ultimately compromising long-term CO₂R performance. Using a flow-cell CO₂R electrolyzer configuration and a copper-coated PTFE GDE, we first show how voltage gradients result in directional in-plane copper migration and porosity changes, causing a decrease in CO and ethylene production due to blocked catalyst pores. By the incorporation of different ionomer and inert carbon overlayers onto copper, we then demonstrate how in-plane degradation is mitigated by modulating the local pH and voltage homogeneity of the electrode, extending ethylene lifetimes by 10-fold. Ultimately, through-plane compaction of copper then becomes the limiting degradation pathway. Combined, these results provide rationale for the paradox of why copper degradation in membrane-electrode assemblies illustrates 100-fold greater stabilities than H-cell and flow-cell architecture.

Correction to: Nature Reviews Materialshttps://doi.org/10.1038/s41578-025-00815-0, published online 16 June 2025. In the version of the article initially published, in Fig. 4b, the labels “Gas-diffusion layer” and “Copper catalyst layer” were switched and have now been amended so that the upper layer is labelled as the “Copper catalyst layer” and the lower layer is the “Gas-diffusion layer”. This correction has been made to the HTML and PDF versions of the article.

Copper and copper-based catalysts can electrochemically convert CO₂ into ethylene and higher alcohols, among other products, at room temperature and pressure. This approach may be suitable for the production of high-value compounds. However, such a promising reaction is heavily burdened by the instability of copper during CO₂ reduction. To date, non-copper catalysts have also failed to supplant the activity and selectivity of copper, leaving CO₂-to-C₂ electrolysis in the balance. In this Perspective, we discuss copper catalyst instability from both the atomistic and the microstructure viewpoint. We motivate that increased fundamental understanding, material design and operational approaches, along with increased reporting of failure mechanisms, will contribute to overcoming the barriers to multi-year operation. Our narrative focuses on the copper catalyst reconstruction occurring during CO₂ reduction as one of the major causes inducing loss of C₂ activity. We conclude with a rational path forward towards longer operations of CO₂-to-C₂ electrolysis.

Zeolitic imidazolate frameworks (ZIFs) based electrocatalysts for CO₂ reduction offer unique possibilities for developing advanced materials for this reaction due to their ordered nanoporosity and pore environments, tunable characteristics and high affinity for CO₂. Still, they were not investigated sufficiently. In this study, we developed a Bismuth nanodots embedded Zeolitic Imidazolate Framework-8 (BND-ZIF-8) electrocatalyst via a one-pot synthesis method for the electrochemical CO₂ reduction reaction (eCO₂RR). Comprehensive spectroscopic and electrochemical characterization confirmed the successful integration of Bismuth into the ZIF-8 matrix. The electrocatalytic performance of the BND-ZIF-8 was assessed in multiple reactor typologies such as H-cell, flow cell, and membrane electrode assembly (MEA) setups. Remarkable differences in the performances in the three cell configurations are evidenced. Notably, the MEA configuration exhibited a marked enhancement in formate selectivity, achieving a Faradic efficiency (FE) of up to 91 % at a current density of −150 mA cm^‒². This work underscores the potential of Bi-ZIF-8 in advancing eCO₂RR while remarking on the crucial importance of the appropriate type of electrocatalytic experiments in assessing the material performance.

Electrochemical ammonia (NH₃) synthesis from nitrate (NO₃⁻) offers a promising greener alternative to the fossil-fuel-based Haber-Bosch process to support the increasing demand for nitrogen fertilizers while removing environmental waste. Previous studies have mainly focused on designing catalysts to promote the direct conversion (NO₃⁻ → NH₃) while suppressing the two-step pathway (NO₃⁻ → NO₂⁻ → NH₃). We hypothesize that efficient nitrate reduction is possible on simple catalysts by instead promoting the two-step reaction and using chemical reactor principles in a membrane electrode assembly, despite NO₂⁻ intermediates. Here, we use an unmodified copper catalyst and control reactivity through current density, flow rate, and electrolyte recycling. Balancing the electrolyte flow rate with current density results in ideal residence times for NO₂⁻, allowing for 91% FE_NH3 in a 5 cm² electrolyzer with a NO₃⁻ to NH₃ partial current of 1.8 A. This work shows that traditional engineering principles can substantially boost the NO₃ reduction reaction, even for simple catalysts.

Using copper (Cu) as an electrocatalyst uniquely produces multicarbon products (C₂₊-products) during the CO₂ reduction reaction (CO2RR). However, the CO2RR stability of Cu is presently 3 orders of magnitude shorter than required for commercial operation. One means of substantially increasing Cu catalyst lifetimes is through periodic oxidative processes, such as cathodic-anodic pulsing. Despite 100-fold improvements, these oxidative methods only delay, but do not circumvent, degradation. Here, we provide an interrogation of chemical and electrochemical Cu oxidative processes to identify the mechanistic processes leading to stable CO2RR through electrochemical and in situ Raman spectroscopy measurements. We first examine chemical oxidation using an open-circuit potential (OCP), identifying that copper oxidation is regulated by the transient behavior of the OCP curve and limited by the rate of the oxygen reduction reaction (ORR). Increasing O₂ flux to the cathode subsequently increased ORR rates, both extending lifetimes and reducing “off” times by 3-fold. In a separate approach, the formation of Cu₂O is achieved through electrochemical oxidation. Here, we establish the minimum electrode potentials required for fast Cu oxidation (−0.28 V vs Ag/AgCl, 1 M KHCO₃) by accounting for transient local pH changes and tracking oxidation charge transfer. Lastly, we performed a stability test resulting in a 20-fold increase in stable ethylene production versus the continuous case, finding that spatial copper migration is slowed but not mitigated by oxidative pulsing approaches alone.