Phytic Acid-Bridged Copper on Sulfur-Containing Carbon Nitride for Enhancing Photocatalytic CO₂ Reduction to CH₃OH

Utilizing artificial photosynthesis to activate the CO₂ reduction reaction and convert it into useful chemicals could drive carbon recycling toward neutrality, effectively addressing global environmental and energy challenges in the long run. Carbon nitride is commonly used as a photocatalytic material, and the introduction of metallic element in the modification process increases the cost of the catalyst. Herein, Cu atoms are uniformly anchored on the surface of sulfur-containing carbon nitride through a convenient phytate acid-bridged approach, resulting in the novel composite catalyst of copper phytate and sulfur-containing carbon nitride (CuPA/SCN). The catalytic performance of CuPA/SCN has been greatly improved, with a CH₃OH evolution rate of 11.87 μmol·g^-1·h^-1, which is nearly 10 times higher than that of SCN. Meanwhile, its excellent selectivity reaches up to 99.38%. Relevant tests and theoretical calculations reveal that CuPA can extract the electrons enriched at the S site and act as conductors. The surface electrons of carbon nitride are rearranged and enriched at S sites, transferred by Cu atoms, thereby promoting the continuous separation of photogenerated electrons and holes. The synergistic effect between CuPA and SCN prolongs charge recombination process, effectively improving the catalytic performance of the samples. This work enriches the complex catalysts of sulfur-containing carbon nitride for the catalytic conversion of carbon dioxide.