Visible light sensitized graphitic carbon nitride based semiconducting materials for photoelectrochemical water splitting

Abstract

Semiconductor based photoelectrochemical water splitting technology directly harvests solar energy into fuels with environment friendly byproducts. The semiconducting material implemented in this technology should be highly photoactive, chemically stable, nontoxic, inexpensive and environmentally benevolent. Even though, various semiconducting materials have been implemented for this purpose, graphitic carbon nitride (GCN) has emerged as an efficient electrode material for water splitting through photoelectrochemical (PEC) route to generate sustainable hydrogen energy owing to its appropriate band position for water reduction reaction, low cost, visible light response, good chemical stability and non-toxicity. However, the practical application of GCN is hindered for PEC water splitting because of numerous challenges, such as its poor electrical conduction ability and high recombination rate. In this paper, we address the fundamental principles for PEC splitting of water with respect to GCN. The broad spectrum of modification strategies for the improvement of GCN based photoelectrodes including heteroelement doping, heterojunction construction, defect engineering and morphology control are also explored. These modification strategies made GCN an efficient material for photoelectrochemical water splitting. The maximum photocurrent density was reported as 320µA cm−2. Conclusively, the crucial challenges and probable solutions for forthcoming advancement in PEC water splitting by GCN based photoelectrodes are highlighted.