Two-dimensional BAs/GeC van der waals heterostructures: A widely tunable photocatalyst for water splitting and hydrogen production

Of late, two-dimensional van der Waals heterostructures (vdWHs) have gained tremendous attention for water-splitting to produce hydrogen (H2) fuel. This work demonstrates various configurations of vdWHs made up of monolayer boron arsenide (BAs) and germanium carbide (GeC) that exhibit outstanding photocatalytic prop-erties in the water-splitting process to generate H2 fuel. The absorption coefficient of the proposed BAs/GeC vdWHs is more than 105 cm-1, which exceeds the extensive conversion efficiency of optoelectronic materials. The absorption coefficient can be further tuned and reaches a maximum value of 2.6 x 105 cm-1 when applying an external strain. Dynamically tunable bandgaps in the range of 0.78-2.02 eV are found in these vdWHs by applying a biaxial strain. A strong photocatalytic water splitting action throughout the ultraviolet to optical spectrum region is found when a biaxial strain of-6% to +6% is applied. The favorable characteristics of the proposed BAs/GeC vdWHs could help enhance H2 fuel generation via water splitting.