Highly Efficient and Stable Hydrogen Production in All pH Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides
Highly Efficient and Stable Hydrogen Production in All pH Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides
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DOI：
10.34133/2019/4029516
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发表时间：
2019-05
期刊：
影响因子：
11
通讯作者：
E. Ang;K. Dinh;Xiaoli Sun;Ying Huang;Jun Yang;Z. Dong;Xiaochen Dong;Wei Huang;Zhiguo Wang;Hua Zhang;Q. Yan
中科院分区：
文献类型：
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作者：
E. Ang;K. Dinh;Xiaoli Sun;Ying Huang;Jun Yang;Z. Dong;Xiaochen Dong;Wei Huang;Zhiguo Wang;Hua Zhang;Q. Yan
通过三氧化钨、聚乙烯吡咯烷酮和金属掺杂剂的混合物渗碳，合成了过渡金属掺杂半碳化钨纳米片（M掺杂W2C NSs， M=Fe、Co和Ni）。纳米片的横向尺寸为几百~几μm，厚度为几十nm。结果表明，掺m的W2C NSs在析氢反应（HER）中表现出优异的电催化活性。令人印象深刻的是，具有优化HER活性的Ni掺杂W2C NSs （2 at% Ni）在酸性（pH=0）、中性（pH=7.2）和碱性（pH=14）溶液中分别表现出极低的起始过电位（4、9和19 mV）和适度的Tafel斜率（39、51和87 mV dec−1），与商用Pt/C催化剂接近。密度泛函数理论（DFT）计算还表明，Ni-W2C吸附H的吉布斯自由能（∆GH = -0.073 eV）比W2C的-0.16 eV更接近最佳值。此外，在这些环境中获得了接近100%的法拉第效率和长期稳定性。这种高耐受性金属半碳化物催化剂在所有pH范围内的性能与商用Pt/C相当，为工业电化学水分解迈出了关键一步。
Transition-metal-doped tungsten semicarbide nanosheets (M-doped W2C NSs, M=Fe, Co, and Ni) have been synthesized through carburization of the mixture of tungsten trioxide, polyvinylpyrrolidone, and metal dopant. The nanosheets grow directly on the W mesh and have the lateral dimension of several hundreds of nm to a few μm with a thickness of few tens nm. It is demonstrated that the M-doped W2C NSs exhibit superior electrocatalytic activity for hydrogen evolution reaction (HER). Impressively, the Ni-doped W2C NSs (2 at% Ni) with the optimized HER activity show extremely low onset overpotentials of 4, 9, and 19 mV and modest Tafel slopes of 39, 51, and 87 mV dec−1 in acidic (pH=0), neutral (pH=7.2), and basic (pH=14) solutions, respectively, which is close to the commercial Pt/C catalyst. Density functional theory (DFT) calculations also demonstrate that the Gibbs free energy for H adsorption of Ni-W2C is much closer to the optimal value ∆GH⁎ = -0.073 eV as compared to -0.16 eV of W2C. Furthermore, nearly 100% Faradaic efficiency and long-term stability are obtained in those environments. This realization of highly tolerant metal semicarbide catalyst performing on par with commercial Pt/C in all range of pH offers a key step towards industrially electrochemical water splitting.