Unassisted photoelectrochemical CO2 reduction by employing III–V photoelectrode with 15% solar‐to‐fuel efficiency

• Published in: Carbon energy Vol. 7; no. 3
• Main Authors: Peramaiah, Karthik, Varadhan, Purushothaman, Ramalingam, Vinoth, Khan, Bilawal, Das, Pradip Kumar, Huang, Hao, Fu, Hui‐Chun, Yang, Xiulin, Tung, Vincent, Huang, Kuo‐Wei, He, Jr‐Hau
• Format: Journal Article
• Language: English
• Published: Beijing John Wiley & Sons, Inc 01.03.2025; Wiley
• Subjects: 3 J photoanode; Carbon dioxide; Carbon monoxide; Chemical reduction; CO2 reduction; Current density; Efficiency; Electrocatalysts; Electrodes; Electrolytes; Energy conversion efficiency; Fourier transforms; Fuels; Grain boundaries; high STF; Metals; Microscopy; Optical properties; Oxidation; Photoanodes; Synthesis gas; unassisted PEC
• ISSN: 2637-9368; 2637-9368
• DOI: 10.1002/cey2.669

Solar‐driven carbon dioxide reduction reaction (CO2RR) provides an opportunity to produce value‐added chemical feedstocks and fuels. However, achieving efficient and stable photoelectrochemical (PEC) CO2RR into selective products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties. Herein, we construct an efficient, concentrated sunlight‐driven CO2RR setup consisting of InGaP/GaAs/Ge triple‐junction cell as a photoanode and oxide‐derived Au (Ox‐Au) as a cathode to perform the unassisted PEC CO2RR. Under one‐sun illumination, a maximum operating current density of 11.5 mA cm–2 with an impressive Faradaic efficiency (FE) of ~98% is achieved for carbon monoxide (CO) production, leading to a solar‐to‐fuel conversion efficiency of ~15%. Under concentrated intensity of 10 sun, the photoanode records a maximum current density of ~124 mA cm–2 and maintains ~60% of FE for CO production. The results demonstrate crucial advancements in using III–V based photoanodes for concentrated PEC CO2RR. We report an unassisted photoelectrochemical (PEC) system using a triple‐junction InGaP/GaAs/Ge integrated with a Ti/RuO x oxygen evolution reaction catalyst as the photoanode and oxide‐derived Au (Ox‐Au) as the cathode. This system shows about 15% solar‐to‐fuel efficiency in the CO2 reduction reaction.