Highly efficient photocatalytic water splitting in direct Z-scheme α-In2Se3/Are van der Waals heterostructures

It has been shown that adopting two-dimensional (2D) semiconductors as photocatalyst for water splitting can be a promising way to achieve green and clean energy. We investigate the heterostructure generated by α-In2Se3 and arsenene (Are) semiconductors manufactured on a wide scale with excellent quality. For water splitting at pH 0, the α-In2Se3/Are heterostructures are shown to provide a direct Z-scheme photocatalytic process that prevents electron–hole recombination and holding an appropriate band edge energy potential for driving the redox reaction. According to the estimated charge density, the Are monolayer is positively charged whereas the α-In2Se3 monolayer is negatively charged. By calculating the Gibbs free energy of the intermediate reactants in water splitting process, α-In2Se3/Are heterostructure demonstrated to be an excellent catalyst for HER and OER. More importantly, the α-In2Se3/Are heterostructures have quite high solar-to hydrogen (STH) efficiency (57.08% for A1 and 24.67% for B3), significantly enhanced compared with isolated α-In2Se3 (18.39%) or Are (6.05%) monolayers. All of data suggest that this α-In2Se3/Are heterostructure with direct Z-scheme can be utilized in photocatalytic water splitting.