Solar-Driven Syngas Production Using Al-Doped ZnTe Nanorod Photocathodes

Syngas, traditionally produced from fossil fuels and natural gases at high temperatures and pressures, is an essential precursor for chemicals utilized in industry. Solar-driven syngas production can provide an ideal pathway for reducing energy consumption through simultaneous photoelectrochemical CO(2) and water reduction at ambient temperatures and pressures. This study performs photoelectrochemical syngas production using highly developed Al-doped ZnTe nanorod photocathodes (Al:ZnTe), prepared via an all-solution process. The facile photo-generated electrons are transferred by substitutional Al doping on Zn sites in one-dimensional arrays to increase the photocurrent density to −1.1 mA/cm(2) at −0.11 V(RHE), which is 3.5 times higher than that for the pristine ZnTe. The Al:ZnTe produces a minor CO (FE ≈ 12%) product by CO(2) reduction and a major product of H(2) (FE ≈ 60%) by water reduction at −0.11 V(RHE). Furthermore, the product distribution is perfectly switched by simple modification of Au deposition on photocathodes. The Au coupled Al:ZnTe exhibits dominant CO production (FE ≈ 60%), suppressing H(2) evolution (FE ≈ 15%). The strategies developed in this study, nanostructuring, doping, and surface modification of photoelectrodes, can be applied to drive significant developments in solar-driven fuel production.