The development of photoelectrochemical (PEC) systems for glycerol valorization and green hydrogen (H₂) production is crucial for advancing sustainable energy technologies. In this work, a novel multilayer CaTiO₃/WO₃/BiVO₄ (CWB) heterostructured photoanode was fabricated via automated spray-coating to promote efficient charge separation and enable glycerol photoelectrooxidation, with photogenerated electrons delivered to a dark cathode to drive the hydrogen evolution reaction (HER). The CWB photoanode operated in a filter-press flow cell, facilitating selective glycerol photoelectrooxidation toward valuable C₁–C₃ compounds, while H₂ was simultaneously produced at a platinum plate dark cathode. At a current density of −10 mA cm⁻² under visible light illumination, glycerol conversion yielded dihydroxyacetone (DHA), glyceric acid (GEA), and formate (HCOO⁻) with an overall Faradaic efficiency (FE) of 64%, achieving a DHA production rate of 124 μmol m⁻² s⁻¹. Concurrently, H₂ was produced at the cathode with a production rate of 549 μmol m⁻² s⁻¹, corresponding to an energy consumption (E_Con) of 383 kWh kmol⁻¹ and a cathodic energy efficiency (CEE) of 74%. The improved performance is attributed to enhanced charge separation promoted by the multilayer heterostructure, with efficient electron transfer across the WO₃/BiVO₄ interface and improved charge collection through the CaTiO₃ layer. These findings demonstrate that replacing the oxygen evolution reaction (OER) with glycerol photoelectrooxidation in multilayer heterostructured photoanodes enables simultaneous H₂ production and generation of value-added chemicals, providing a promising platform for integrated PEC systems.

The electrochemical reduction of CO₂ using copper-based catalysts represents a promising pathway for producing multi-carbon products from renewable energy. Temperature is a key parameter that not only determines reaction pathways and product selectivity but also strongly affects catalyst stability, electrolyte composition, and membrane integrity. Despite its importance, most studies have primarily focused on catalytic selectivity, often overlooking the thermal and stability aspects recently emphasized in the literature. This perspective underscores the central role of temperature in governing both catalytic performance and the physical and chemical resilience of electrolyzer components under low-temperature (20–80 °C) conditions. These factors become even more critical during scale-up, where heat management and transfer directly influence efficiency and long-term durability, similar to challenges in hydrogen production systems. A comprehensive understanding of thermal effects on both catalytic and non-catalytic elements is therefore essential for optimizing system performance. This work proposes experimental methodologies to evaluate the thermal and chemical stability of catalysts, electrolytes, and membranes, and outlines future research directions aimed at enabling the practical, efficient, and scalable deployment of CO₂ electrolysis through improved thermal design and integrated heat management.