| Energy crisis and environmental pollution is a hotspot issue in today's world. New types of renewable clean energy are actively explored. Among them, hydrogen is considered to be the most promising one because of high efficiency and clean. Making use of renewable energy sources as the power of water electrolysis is the best way to generate hydrogen energy. At present, Pt and other precious metal materials are still identified as the most active catalysts for hydrogen evolution reaction (HER). However, precious metals are scare and high-cost. Therefore, the development of high-performance and low-cost catalysts has become the key to water electrolysis. Nickel and nickel-based alloys are the ideal alternatives to Pt-based catalysts for their high activity and good stability. There are two main ways to improve the performance of nickel-based catalysts, one is to prepare nano-/nanoporous catalysts, the other is to select appropriate supporters for the catalysts.Hierarchical porous nanomaterials have a wide range of applications in the fields of adsorption, fuel cell, energy storage, catalysis and so on due to the advantages of different pore sizes. More catalytic active sites are provided because of higher specific surface area, and better mass transfer in macroporous facilitates the diffusion of reactants and products. Therefore, this nanomaterials have become excellent catalyst supporters. In this paper, three dimensionally ordered macro-/mesoporous carbon ( OMMC ) materials supported Ni2P nanoparticles are synthesized. The main works and results are summarized as follows:OMMC is fabricated through a dual-templating synthesis approach by using silica colloidal crystal as hard template and surfactant P123 as soft template. The as-prepared OMMC exhibits interconnected marcoporous structure with ordered mesopores locating in the macropore walls. It shows an average pore diameter of 8.3 nm and a high BET surface area of 1129 m2 g-1.The OMMC can be used as an excellent catalyst supporter due to the enhanced mass transfer in the macropores and higher specific surface area.OMMC supported Ni2P particles are synthesized by thermal decomposition of hypophosphite. NiCl2·6H2O and NaH2PO2 are used as nickel source and phosphorous source respectively. By varying the mass of NiCl2 ·6H2O and NaH2PO2, a series of samples with different Ni2P loading (60,40, and 20 wt%) was also synthesized. Ni2P loading does not destroy the original structure of OMMC. It can be found that 40 wt% Ni2P/OMMC exhibits the highest electrocatalytic performance for the HER among the three catalysts. The onset overpotential of 40 wt% Ni2P/OMMC was 47 mV, and the overpotential at the current density of -10 mA cm-2 was 143 mV.Ni2P nanoparticles (Ni2P NPs) and 40 wt% Ni2P/carbon black(Ni2P/XC-72R) were prepared as the comparative catalysts. Compared to Ni2P NPs and 40 wt% Ni2P/XC-72R, the Ni2P particles supported by OMMC are more uniform and have a smaller particle size of 4.5 nm, due to the effective restrictions of macro-/mesoporous structure on particles' growth and aggregation. 40 wt% Ni2P/OMMC also exhibits enhanced electrocatalytic activity for the HER, which illustrates OMMC's superiority as a catalyst supporter. |
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