Urchinlike W₁₈O₄₉/g‑C₃N₄ Z‑Scheme Heterojunction for Highly Efficient Photocatalytic Reduction of CO₂ under Full Spectrum Light

In this work, an urchinlike W₁₈O₄₉/g-C₃N₄ composite was fabricated via a simple hydrothermal process. The photocatalytic CO₂ conversion reaction was applied to evaluate the photocatalytic behavior of this catalytic system, and the WOCN-20 wt % heterojunction displayed superior photocatalytic behavior under full spectrum light irradiation, which was 6.46 μmol·h^–1·g^–1 for CO and 3.97 μmol·h^–1·g^–1 for CH₄, respectively. Furthermore, in the near-infrared region, the composite photocatalysts also displayed excellent photocatalytic performance. A large number of characterizations and testing measures were carried out to study the components, morphology, and physicochemical properties of W₁₈O₄₉/g-C₃N₄ photocatalyst, which were helpful to exploring and understanding the reasons for the improvement of catalytic performance. The boosted activity resulted from the tight contact between W₁₈O₄₉ and g-C₃N₄ and the formation of a Z-scheme heterojunction. The local surface plasmonic resonance (LSPR) of W⁵⁺ also contributed to the realization of efficient photocatalysis under near-infrared light. The Z-scheme electron transport model could realize the efficient separation of light-induced e^––h⁺ pairs and reduce the recombination rate, thereby boosting the CO₂ photocatalytic reduction process.