Coupling furfural oxidation for bias-free hydrogen production using crystalline silicon photoelectrodes
Myohwa Ko, Myounghyun Lee, Taehyeon Kim, Wonjoo Jin, Wonsik Jang, Seon Woo Hwang, Haneul Kim, Ja Hun Kwak, Seungho Cho, Kwanyong Seo, Ji‐Wook Jang
Abstract
To commercialize the technology of photoelectrochemical hydrogen production, it is essential to surpass the US. Department of Energy target of 0.36 mmol h−1 cm−2 for 1-sun hydrogen production rate. In this study, we utilize crystalline silicon, which can exhibit the highest photocurrent density (43.37 mA cm−2), as the photoelectrode material. However, achieving bias-free water splitting (>1.6 V) remains challenging due to the intrinsic low photovoltage of crystalline silicon (0.6 V). To address this limitation, we replace water oxidation with low-potential furfural oxidation, enabling not only bias-free hydrogen production but also dual hydrogen production at both the cathodic and anodic sides. This approach results in a record 1-sun hydrogen production rate of 1.40 mmol h−1 cm−2, exceeding the Department of Energy target by more than fourfold. The authors demonstrate a bias-free dual solar hydrogen production system by pairing low-potential furfural oxidation with a Si photocathode, achieving a 1-sun hydrogen production rate that surpasses the Department of Energy target by over four-fold.