Graphitic carbon nitride (g-C₃N₄)-based photocatalysts holds great promise on photocatalytic CO₂ conversion into solar fules; however, the efficiency of pristine g-C₃N₄ is currently limited by its poor visible light absorption and rapid charge recombination. Employing silver chromate (Ag₂CrO₄) nanoparticles as photosensitizer and graphene oxide (GO) as cocatalyst, a novel ternary Ag₂CrO₄/g-C₃N₄/GO composite photocatalyst was fabricated for photocatalytic CO₂ reduction into methanol (CH₃OH) and methane (CH₄). The ternary composites exhibited an enhanced CO₂ conversion activity with a turnover frequency of 0.30 h^–1, which was 2.3 times that of pristine g-C₃N₄ under simulated sunlight irradiation. The enhanced photocatalytic activity was due to broadened light absorption, higher CO₂ adsorption and more efficient charge separation. Specifically, due to the matched band structure and appropriate loading ratio of Ag₂CrO₄, a direct Z-scheme Ag₂CrO₄/g-C₃N₄ heterojunction is formed, driven by the internal electric field across the Ag₂CrO₄/g-C₃N₄ interface. The formation of the direct Z-scheme heterojunction is substantiated by radical scavenging experiments and density functional theory calculations, and it benefits the photocatalytic reaction by accelerating the charge separation and improving the redox ability. Furthermore, GO cocatalyst not only promotes the charge transfer but also provides plentiful CO₂ adsorption and catalytic sites. This work exemplifies the facile development of ternary g-C₃N₄-based photocatalysts with high CO₂-conversion activity by coupling a small amount of Ag-based photosensitizer and metal-free cocatalyst.

石墨化的氮化碳（gC ₃ N ₄）基光催化剂在将光催化的CO ₂转化为太阳能电池方面具有广阔的前景。然而，原始的gC ₃ N ₄的效率目前受到可见光吸收差和电荷快速重组的限制。以铬酸银（Ag ₂ CrO ₄）为光敏剂，氧化石墨烯（GO）为助催化剂，制备了新型三元Ag ₂ CrO ₄ / gC ₃ N ₄ / GO复合光催化剂，用于将CO ₂光催化还原为甲醇（CH _3）。OH）和甲烷（CH ₄）。在模拟阳光照射下，三元复合材料显示出增强的CO ₂转化活性，转换频率为0.30 h ^–1，是原始gC ₃ N _4的2.3倍。增强的光催化活性归因于更宽的光吸收，更高的CO ₂吸附和更有效的电荷分离。具体地，由于匹配的能带结构和Ag ₂ CrO _4的合适的负载比，直接Z方案Ag ₂ CrO ₄ / gC ₃ N ₄在内部电场的作用下，跨Ag ₂ CrO ₄ / gC ₃ N ₄界面形成异质结。直接Z方案异质结的形成通过自由基清除实验和密度泛函理论计算得到证实，并且它通过加速电荷分离和提高氧化还原能力而有益于光催化反应。此外，GO助催化剂不仅促进电荷转移，而且提供大量的CO ₂吸附和催化位点。这项工作例证了具有高CO ₂的三元基于gC ₃ N ₄的三元光催化剂的简便开发偶合少量的基于银的光敏剂和不含金属的助催化剂可实现高转化活性。