Recent advances in graphitic carbon nitride-based photocatalysts for solar-driven hydrogen production

Due to the abundance and sustainability of solar energy, converting it into chemical energy to obtain clean energy presents an ideal solution for addressing environmental pollution and energy shortages stemming from the extensive combustion of fossil fuels. In recent years, hydrogen energy has emerged on the stage of history as the most promising clean energy carrier of the 21st century. Among the current methods of producing hydrogen, photocatalytic hydrogen production technology, as a zero-carbon approach to producing high calorific value and pollution-free hydrogen energy, has attracted much attention since its discovery. As the core of photocatalysis technology, semiconductor photocatalysts are always the research hotspots. Among them, graphite-phase carbon nitride (g-C3N4), an organic semiconductor material composed of only C and N elements, possesses physicochemical properties incomparable to those of traditional inorganic semiconductor materials, including suitable energy band positions, easy structural regulation, inexpensive raw materials and abundant reserves, simple preparation, high thermal/mechanical/chemical stability, etc. Therefore, g-C3N4 has attracted extensive attention in the field of photocatalytic hydrogen production in the last two decades. This review comprehensively outlines the research trajectory of g-C3N4 photocatalytic hydrogen production, encompassing development, preparation methods, advantages, and disadvantages. A concise introduction to g-C3N4 is provided, as well as an analysis of the underlying mechanism of the photocatalytic system. Additionally, it delves into the latest techniques to enhance performance, including nanostructure design, elemental doping, and heterojunction construction. The applications of g-C3N4 based photocatalysts in hydrogen production are surveyed, underscoring the significance of catalyst active sites and g-C3N4 synthesis pathways. At length, concluded are insights into the challenges and opportunities presented by g-C3N4 based photocatalysts for achieving heightened hydrogen production.