Crystal Facet Effect of WO3 in Heterogeneous Catalysis: A Review
Tungsten trioxide (WO3) is a transition metal oxide of significant interest in heterogeneous catalysis due to its environmental friendliness, cost-effectiveness, and favorable electrical properties. The catalytic performance of WO3 is strongly dependent on its exposed crystal facets, which exhibit distinct physicochemical properties including charge separation efficiency, reactant adsorption capacity, and redox activity. These differences arise from variations in atomic arrangement, electronic structure, and surface energy. This review systematically examines the facet effect of WO3 across photocatalysis, electrocatalysis, photoelectrocatalysis, and thermal catalysis. Theoretical calculations are integrated to elucidate the intrinsic mechanisms underlying facet-dependent behavior from an atomic structure perspective. The paper synthesizes general rules governing the WO3 facet effect across these applications, critically assesses current research limitations, and outlines future directions. Key findings highlight that facet engineering enables precise tuning of catalytic activity and selectivity, with specific facets such as {001}, {110}, and {010} demonstrating enhanced performance in various reactions. The review underscores the importance of morphology control in optimizing WO3-based catalysts and identifies challenges in achieving facet-selective synthesis and stability under operational conditions. Future research should focus on advanced characterization techniques and computational modeling to further unravel facet-dependent mechanisms and guide rational catalyst design.