Search

Water evaporation and steam production have been recognized to be considerably crucial due to the vast applications, ranging from waste water treatment, water purification, to alternative green energy solutions by water splitting, catalysis, and in-door heating. Albeit the big variety of photothermal conversion materials (PCMs) developed for this purpose, certain drawbacks, e.g. high cost, complicated synthesis, weak/narrow absorbance, bulkiness, and low evaporation rate, have hindered the application potential. Herein, we report the dual-phase molybdenum nitride nanorambutans, synthesized by a facile method, for solar steam generation. Not only the inherent properties, including strong full-spectrum absorbance, high-efficiency photothermal conversion, and super-hydrophilicity, benefit their water evaporation performance, the interconnected open mesopores of the nanorambutans further boost their capability of light harvesting and water/vapor transportation. Solar energy conversion efficiency of ∼97% under one sun together with excellent cycling stability has been demonstrated. In the desalination systems, integrating with the high salt rejection rate, the nanorambutans film can produce a water evaporation rate as high as ∼1.70 kg m −2 h −1 with an efficiency of ∼98%. Besides its compact size, the record-breaking water evaporation performance of these nanorambutans has exceeded the previous best inorganic PCM. This work introduces molybdenum nitride as a new PCM for efficient solar steam generation and all applications that can benefit from highly localized heating from nano to macro scale.

Nickel-based alloy catalysts are promising candidates to replace noble metal materials for electrocatalytic hydrogen evolution reaction (HER), but the performance of the alloy systems still needs to be improved to effectively substitute noble metal catalysts, such as platinum. Here we report a detailed study of the controlled deposition of NiMoZn ternary alloy electrocatalysts and we subsequently investigate the influence of chemical composition on the HER reactivity. We have identified the essential role of Zn for boosting the intrinsic electrocatalytic performance and revealed the optimum Zn concentration in the alloy. While the low concentration of Zn facilitates the charge transfer process, massive Zn deposition in the alloy results in a strong inhibition of proton adsorption on the surface of the electrocatalysts. The NiMoZn alloy electrocatalyst with a Zn concentration of 1–3 at% shows an extremely high activity for HER, which is significantly higher than that of most non-noble metal electrocatalysts. Moreover, the alloy with 2 at% of Zn exhibits an excellent stability in acid conditions, featuring the NiMoZn alloy a promising candidate to replace noble metal electrocatalyst for water splitting process.