Chu Xuan, Santos-Carballal David, de Leeuw Nora H
School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
Department of Earth Sciences, Utrecht University, Princetonplein 8A, Utrecht 3584 CD, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2023 Sep 15;127(38):18944-18961. doi: 10.1021/acs.jpcc.3c04413. eCollection 2023 Sep 28.
Photocatalysis has gained significant attention and interest as an environmentally friendly and sustainable approach to the production of hydrogen through water splitting and the reduction and conversion of CO. Copper tungstate (CuWO) is a highly promising candidate for these applications owing to its appropriate bandgap and superior stability under different conditions. However, the redox behavior of the CuWO surfaces under different environments and their impact on the morphology of the material nanoparticles, as well as the electronic properties, remain poorly understood. In this study, we have employed density functional theory calculations to investigate the properties of the bulk and pristine surfaces of CuWO and how the latter are impacted by oxygen chemisorption under the conditions required for photocatalytic water splitting and carbon dioxide reduction processes. We have calculated the lattice parameters and electronic properties of the bulk phase, as well as the surface energies of all possible nonpolar, stoichiometric, and symmetric terminations of the seven low-Miller index surfaces and found that the (010) and (110) facets are the thermodynamically most stable. The surface-phase diagrams were used to derive the equilibrium crystal morphologies, which show that the pristine (010) surface is prominent under synthesis and room conditions. Our crystal morphologies suggest that the partially oxidized (110) surface and the partially reduced (011) surface may play an important role in the photocatalytic splitting of water and CO conversion, respectively. Our results provide a comprehensive understanding of the CuWO surfaces under the conditions of important photocatalytic applications.
作为一种通过水分解生产氢气以及还原和转化一氧化碳的环境友好且可持续的方法，光催化已引起了广泛关注和兴趣。由于其合适的带隙以及在不同条件下的卓越稳定性，钨酸铜（CuWO）是这些应用中极具潜力的候选材料。然而，对于不同环境下CuWO表面的氧化还原行为及其对材料纳米颗粒形态以及电子性质的影响，人们仍然知之甚少。在本研究中，我们采用密度泛函理论计算来研究CuWO体相和原始表面的性质，以及在光催化水分解和二氧化碳还原过程所需条件下，后者如何受到氧化学吸附的影响。我们计算了体相的晶格参数和电子性质，以及七个低米勒指数表面所有可能的非极性、化学计量和对称终止的表面能，发现(010)和(110)晶面在热力学上最稳定。利用表面相图推导出平衡晶体形态，结果表明在合成和室温条件下原始(010)表面最为突出。我们的晶体形态表明，部分氧化的(110)表面和部分还原的(011)表面可能分别在水的光催化分解和CO转化中起重要作用。我们的结果为重要光催化应用条件下的CuWO表面提供了全面的理解。
