Zhang Yanzhao, Johannessen Bernt, Zhang Peng, Gong Jinlong, Ran Jingrun, Qiao Shi-Zhang
School of Chemical Engineering, The University of Adelaide, Adelaide, South Australia, 5005, Australia.
Australian Synchrotron, 800 Blackburn Rd, Clayton, Victoria, 3168, Australia.
Adv Mater. 2023 Nov;35(44):e2306923. doi: 10.1002/adma.202306923. Epub 2023 Sep 20.
Photogenerated charge localization on material surfaces significantly affects photocatalytic performance, especially for multi-electron CO reduction. Dual single atom (DSA) catalysts with flexibly designed reactive sites have received significant research attention for CO photoreduction. However, the charge transfer mechanism in DSA catalysts remains poorly understood. Here, for the first time, a reversed electron transfer mechanism on Au and Co DSA catalysts is reported. In situ characterizations confirm that for CdS nanoparticles (NPs) loaded with Co or Au single atoms, photogenerated electrons are localized around the single atom of Co or Au. In DSA catalysts, however, electrons are delocalized from Au and accumulate around Co atoms. Importantly, combined advanced spectroscopic findings and theoretical computation evidence that this reversed electron transfer in Au/Co DSA boosts charge redistribution and activation of CO molecules, leading to highly significantly increased photocatalytic CO reduction, for example, Au/Co DSA loaded CdS exhibits, respectively, ≈2800% and 700% greater yields for CO and CH compared with that for CdS alone. Reversed electron transfer in DSA can be used for practical design for charge redistribution and to boost photoreduction of CO . Findings will be of benefit to researchers and manufacturers in DSA-loaded catalysts for the generation of solar fuels.
光生电荷在材料表面的局域化显著影响光催化性能，特别是对于多电子CO还原反应。具有灵活设计的反应位点的双单原子（DSA）催化剂在CO光还原反应方面受到了广泛的研究关注。然而，DSA催化剂中的电荷转移机制仍知之甚少。在此，首次报道了Au和Co DSA催化剂上的反向电子转移机制。原位表征证实，对于负载有Co或Au单原子的CdS纳米颗粒（NPs），光生电子局域在Co或Au的单原子周围。然而，在DSA催化剂中，电子从Au离域并在Co原子周围积累。重要的是，先进的光谱研究结果和理论计算相结合证明，Au/Co DSA中的这种反向电子转移促进了电荷重新分布和CO分子的活化，从而导致光催化CO还原反应显著增强，例如，负载Au/Co DSA的CdS与单独的CdS相比，CO和CH的产率分别提高了约2800%和700%。DSA中的反向电子转移可用于电荷重新分布的实际设计，以促进CO的光还原。这些发现将有助于研究人员和制造商开发用于太阳能燃料生产的负载DSA的催化剂。
