Comprehensive First-Principles Study on the Multifaceted Properties of Four BiVO4 Polymorphs: Unraveling the Structure–Property Relationships

Abstract

Bismuth vanadate (BiVO4) has emerged as a widely studied photocatalytic material for water splitting and pollutant degradation owing to its favorable band gap of approximately 2.4 eV, favorable chemical stability, and environmental compatibility. Using first-principles calculations, we systematically investigated the multiscale properties of four BiVO4 polymorphs (sm, op, zt, and st-BiVO4). Results demonstrate that sm-BiVO4 exhibits the narrowest band gap (2.23 eV) among the four polymorphs and the highest adsorption stability, with only one unstable configuration identified among 21 adsorbate–facet combinations. This superior stability is attributed to structural distortion that induces local polarization and lone-pair electrons, which effectively facilitate the separation of photogenerated charge carriers. This polymorph also exhibits higher visible light absorption coefficients than those of st-BiVO4 across the energy range of 2.06–3.50 eV and shows stable surface adsorption. Thermodynamically, zt-BiVO4 is more stable, whereas mechanical analysis reveals that sm-BiVO4 possesses high hardness and modulus but lower ductility. This study systematically elucidates the structure–property relationships of BiVO4 from electronic, optical, adsorptive, thermodynamic, and mechanical perspectives, thereby establishing a theoretical foundation for the rational optimization of its photocatalytic performance.