Abstract：Carbon-coated cobalt phosphide (CoP/C) powders were prepared by high temperature pre-annealing and further phosphating using Zeolitic Imidazolate Framework-67 (ZIF-67) and Co(NO3)2∙6H2O as precursor. CoP/C powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the electrocatalytic hydrogen evolution experiments were also carried out. The results show that after calcination at high temperature, the organic components of ZIF-67 are transformed into conductive carbon skeleton, and cobalt ions are transformed into elemental cobalt nanoparticles embedded in the carbon skeleton. After further phosphating, pure phase CoP/C powders are obtained. CoP/C powders exhibit good catalytic activity with an overpotential of 64 mV and a Tafel slope of 66 mV/dec, which maintains high catalytic activity after 15 h for electrocatalytic hydrogen evolution.
[1] DUNN B, KAMATH H, TARASCON J M.Electrical energy storage for the grid: A battery of choices[J]. Science, 2011, 334(6058): 928-935. [2] LU X F, YU L, LOU X W. Highly crystalline Ni-doped FeP/carbon hollow nanorods as all-pH efficient and durable hydrogen evolving electrocatalysts[J]. Science Advances, 2019, 5(2): eaav6009. [3] SKULASON E, KARLBERG G S, ROSSMEISL J, et al.Density functional theory calculations for the hydrogen evolution reaction in an electrochemical double layer on the Pt(111) electrode[J]. Phys Chem Chem Phys, 2007, 9(25): 3241-3250. [4] ZHANG H, NAI J, YU L, et al.Metal-organic-framework-based materials as platforms for renewable energy and environmental applications[J]. Joule, 2017, 1(1): 77-107. [5] WANG H, TSAI C, KONG D, et al.Transition-metal doped edge sites in vertically aligned MoS2 catalysts for enhanced hydrogen evolution[J]. Nano Research, 2015, 8(2): 566-575. [6] KIBSGAARD J, TSAI C, CHAN K, et al.Designing an improved transition metal phosphide catalyst for hydrogen evolution using experimental and theoretical trends[J]. Energ Environ Sci, 2015, 8(10): 3022-3029. [7] YAN H, XIE Y, JIAO Y, et al.Holey reduced graphene oxide coupled with an Mo2 N-Mo2 C heterojunction for efficient hydrogen evolution[J]. Advanced Materials, 2018, 30(2): 1407156 [8] CARIM A I, SAADI F H, SORIAGA M P, et al.Electrocatalysis of the hydrogen-evolution reaction by electrodeposited amorphous cobalt selenide films[J]. J Mater Chem A, 2014, 2(34): 13835-13839. [9] SHI Y, ZHANG B.Recent advances in transition metal phosphide nanomaterials: Synthesis and applications in hydrogen evolution reaction[J]. Chemical Society Reviews, 2016, 45(6): 1529-1541. [10] YAN L, DAI P, WANG Y, et al.In situ synthesis strategy for hierarchically porous Ni2P polyhedrons from MOFs templates with enhanced electrochemical properties for hydrogen evolution[J]. ACS Appl Mater Interfaces, 2017, 9(13): 11642-11650. [11] ZHAO X, YANG H, JING P, et al.A metal-organic framework approach toward highly nitrogen-doped graphitic carbon as a metal-free photocatalyst for hydrogen evolution[J]. Small, 2017, 13(9): 1603279. [12] DANG S, ZHU Q L, XU Q.Nanomaterials derived from metal- organic frameworks[J]. Nature Reviews Materials, 2017, 3(1): 17075-17089. [13] FANG G, WANG Q, ZHOU J, et al.Metal organic framework- templated synthesis of bimetallic selenides with rich phase boundaries for sodium-ion storage and oxygen evolution reaction[J]. ACS Nano, 2019, 13(5): 5635-5645. [14] PAN Y, SUN K, LIU S, et al.Core-shell ZIF-8@ZIF-67-derived CoP nanoparticle-embedded N-doped carbon nanotube hollow polyhedron for efficient overall water splitting[J]. J Am Chem Soc, 2018, 140(7): 2610-2618. [15] MA F X, WU H B, XIA B Y, et al.Hierarchical β-Mo2C nanotubes organized by ultrathin nanosheets as a highly efficient electrocatalyst for hydrogen production[J]. Angew Chem Int Ed, 2015, 54(51): 15395-15399.
2019, Vol. 24 
