Multiple-atomic asymmetry effect on polarization-controlled photocatalytic properties in two-dimensional single-layer materials.

Two-dimensional asymmetric materials with intrinsic polarization are promising for photocatalytic water-splitting applications. However, achieving efficient polarization modulation in a single asymmetric material to promote photocatalytic solar-to‑hydrogen conversion remains challenging, given that it requires photocatalysts capable of controlled polarization with promoted catalytic reactions. Here, using the first-principles calculation, we report that the catalytic activities can be enhanced by adjusting multiple-atomic asymmetry in a single-layer material of MoSiGeX2Y2 (X, Y = N, P, As; X ≠ Y). The regulation mechanism of multiple-atomic asymmetry on the photocatalytic process is thoroughly elucidated. Benefiting from the enhanced polarization induced by multiple-atomic asymmetry, the energy barriers for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the MoSiGeP2N2 monolayer are significantly decreased, thereby improving photocatalysis. Moreover, its efficient optical absorption and high photocurrent peak endow MoSiGeP2N2 excellent photoelectric conversion behavior. This work reveals the effect of multiple-atomic asymmetry on polarization-controlled photocatalysis and offers new insights for boosting photocatalytic performance.