Photoelectrochemical catalytic CO2 reduction enhanced by In-doped GaN and combined with vibration energy harvester driving CO2 reduction

Photoelectrochemical (PEC) technology seamlessly integrates and optimizes the merits of photocatalysis and electrocatalysis, facilitating charge separation and enhancing solar conversion efficiency. It stands out as a promising approach for CO₂ treatment. GaN as III-Ⅴ semiconductor, has garnered substantial attention in the realm of PEC CO₂ reduction reactions (RR). In this study, GaN and In/GaN micro-rods were prepared via straightforward hydrothermal synthesis. Attaining a current density of approximately 10 mA/cm² and CO Faradaic Efficiency (FE) of ∼45 % at −0.75 V_RHE (Reversible Hydrogen Electrode, RHE), In/GaN exhibited exceptional stability over a 2 h PEC CO₂ RR. The introduction of In into GaN significantly augmented CO₂ adsorption capacity and light harvesting. Additionally, Density Functional Theory (DFT) calculations elucidated that In-doped GaN can diminish the adsorption of intermediate CO, favoring subsequent CO desorption. Furthermore, the N-vacancy increased with In doping, resulting in a rise in the number of unpaired electrons, facilitating carrier transport. Herein, vibration energy harvester was introduced to drive CO₂ RR, marking a significant advancement in development of PEC CO₂ RR for future green energy applications.