Sulfoxide-Functional Nanoarchitectonics of Mesoporous Sulfur-Doped C3N5 for Photocatalytic Hydrogen Evolution

While carbon nitrides have emerged as leading materials in photocatalysis over the past two decades, innovative and facile approaches for porosity engineering (to enhance effective surface area) and atomistic heteroatom doping (to boost catalytic activity) are presently being hunted. We herein report the first synthesis of mesoporous sulfur-doped C3N5 (mesoporous sulfur-doped carbon nitrides (MSCNs)) with sulfoxide-functionalization via pyrolysis of 5-amino-1,3,4-thiadiazole-2-thiol, utilizing nanoporous silica templates with 2D and 3D porous structures (KIT-6 and SBA-15). Morphological and physicochemical properties of MSCNs have been systematically evaluated. We demonstrate that highly ordered mesoporous structural features with high effective surface areas, sulfur doping, and generated defects significantly dampen exciton recombination. In addition, adequate doping and functionalization yielding a sufficient number of catalytically active sites constitute the favorable set of conditions, eventually resulting in a remarkable hydrogen generation rate of 1370 μmol g–1 h–1 and effective pollutant remediation (>97% degradation rate in 150 min). Spectroscopic investigations and density functional theory calculations reveal that the sulfoxide functionalities generate efficient charge-transfer pathways on the catalyst's surface, thereby catalyzing the reaction and impeding charge carrier recombination. The implications of this research offer insights into the development of surface/interface engineering and atomistic doping for enhanced photocatalysis, which will inspire superior futuristic catalytic design.