Designing hierarchical heterostructure to optimize the adsorption of hydrogen intermediate (H*) is impressive for hydrogen evolution reaction (HER) catalysis. Herein, we show that vertically mounting two-dimensional (2D) layered molybdenum disulfide (MoS₂) nanosheets on 2D nonlayered dimolybdenum carbide (Mo₂C) nanomeshes to form a hierarchical heterostructure largely accelerates the HER kinetics in acidic electrolyte due to the weakening adsorption strength of H* on 2D Mo₂C nanomeshes. Our hierarchical MoS₂/Mo₂C heterostructure therefore gives a decrease of overpotential for up to 500 mV at −10 mA·cm⁻² and an almost 200-fold higher kinetics current density compared with the pristine Mo₂C nanomeshes and maintains robust stability with a small drop of overpotential for only 16 mV upon 5,000 cycles. We further rationalize this finding by theoretical calculations and find an optimized adsorption free energy of H*, identifying that the MoS₂ featuring strong H* desorption plays a key role in weakening the strong binding of Mo₂C with H* and therefore improves the intrinsic HER activity on active C sites of Mo₂C. This present finding shines the light on the rational design of heterostructured catalysts with synergistic geometry.

Solar interface water evaporation has been demonstrated to be an advanced method for freshwater production with high solar energy utilization. The development of evaporators with lower cost and higher efficiency is a key challenge in the manufacture of practical solar interface water evaporation devices. Herein, a bamboo leaf-derived carbon-based evaporator is designed based on the light trace simulation. And then, it is manufactured by vertical arrangement and carbonization of bamboo leaves and subsequent polyacrylamide modification. The vertically arranged carbon structure can extend the light path and increase the light-absorbing area, thus achieving excellent light absorption. Furthermore, the continuous distribution of polyacrylamide hydrogel between these vertical carbons can support high-speed water delivery and shorten the evaporation path. Therefore, this evaporator exhibits an ultrahigh average light absorption rate of ˜96.1%, a good water evaporation rate of 1.75 kg m^–2 h⁻¹, and an excellent solar-to-vapor efficiency of 91.9% under one sun irradiation. Furthermore, the device based on this evaporator can effectively achieve seawater desalination, heavy metal ion removal, and dye separation while completing water evaporation. And this device is highly available for actual outdoor applications and repeated recycling.