Advances/Scope and prospects of g-C3N4 derived fascinating photocatalyst as a leading route towards solar energy adaption

The formation and conservation of renewable radiation into chemical fuels via photocatalytic water splitting (WS) maintains a perspective for maximizing the economic condition and limiting the worldwide climate consequence. Photocatalytic water splitting (PWS) employing powdered semiconductors has enormous opportunity for sustainable fuel, since this crossroad connecting biological, material science, and physical sciences depicts a field with exciting multidisciplinary issues. Development in PWS has been accomplished in past decades, encompassing from basic science investigation to innovative extensible technologies. Semiconductor-based photocatalysis is regarded as a potential sustainable solution. In this regard, graphitic carbon nitride (g-C3N4) is classed as a metal-free photocatalyst to overcome this energy demand and ecological challenges, because of its superior electronic structure with band energy of around 2.7 eV, strong photochemical stabilization, and higher light efficiency. The photocatalytic activity of g-C3N4 is inadequate, because of its small surface area (SA) and high rate of charge recombination. Various chemical alteration techniques have been developed to address such problems, broaden the functionality ranges, and improve the characteristics of g-C3N4. The present review provides an in-depth evaluation of the chemical modification techniques for g-C3N4, comprising covalently and non-covalently techniques. Covalent techniques demonstrate the formation of chemical bonding among the g-C3N4 configuration and the chemical activator via oxidation/carboxylation, amidation, composite inoculation, etc., even though non-covalent techniques entail the formation of physiological bonds and interfacial properties via van der Waals connections, hydrophobic forces, etc. After these fabrication approaches, the photocatalytic performance increased due to the generation of photoinduced electrons and holes, improved light absorption ability, and boosted SA, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C3N4 to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting the photocatalytic performance. Also, different varieties of g–C3N4–based materials have been utilized for different aspects of photocatalytic applications such as water reduction (HER), water oxidation (OER), and overall water splitting (OWS). Therefore, we have assembled a summary of the latest modern g-C3N4 nanocomposites, as well as their uses in solar energy adaptation and environmental management. This research explains the details of the mechanism for all these photocatalytic processes for the next steps, as well as many new insights to overcome the current challenges.