动态表面重建控制了基介质中的Mo2C电催化剂的演变活性
Palash Jyoti Gogoi1,2, Chandraraj Alex1,3, Swetarekha Ram4
1Centre for Nano and Soft Matter Sciences (CeNS), Shivanapura, Bengaluru 562162, India. jsneena@cens.res.in.
Materials horizons
|March 16, 2026
概括
碳化 (Mo2C) 催化剂的演化反应 (HER) 显示高活性,由于一个自我限制的表面重建形成Mo2C@MoO2-x. 这种受控的氧化,而不是金属Mo,是高效性水电解的关键.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
背景情况:
- 碳化 (Mo2C) 是演化反应 (HER) 的一个有希望的地球丰富的催化剂.
- 表面氧化对HER的Mo2C催化剂性能的影响尚不清楚.
- 了解工作条件下的催化剂演变对于设计高效的电催化剂至关重要.
研究的目的:
- 研究表面氧化物种对Mo2C催化剂HER性能的影响.
- 在HER条件下比较原始Mo2C和Mo/Mo2C异构的活性和结构演变.
- 阐明表面重建在增强催化剂稳定性和活性中的作用.
主要方法:
- 通过碳热还原合成Mo2C和Mo/Mo2C异构结构.
- 在现场Mo K边缘X射线吸收光谱 (XAS) 和拉曼光谱来监测结构变化.
- 电化学测量以评估 HER 活性 (10 mA cm-2 的超电位).
- 密度函数理论 (DFT) 计算以了解反应机制和结合能.
主要成果:
- 与原始的Mo2C (117 mV) 相比,Mo/Mo2C异构体表现出较低的HER活性 (204 mV).
- 这两种催化剂都氧化为四氧化氧 (MoO4) 2− 基因,但Mo/Mo2C显示出更快,更广泛的氧化.
- Mo2C稳定了富含缺陷的MoOx层 (类似MoO2),增强了HER活性,而Mo/Mo2C经历了有害的氧化转化.
- 在Mo2C上现场形成的Mo2C@MoO2-x物种显示出高的HER活性和再生能力.
结论:
- 在Mo2C基催化剂中,高HER活性的关键在于可控制的,自我限制的表面重建,形成Mo2C@MoO2-x.
- 这种重建的层通过保持适度的Mo-H结合来优化吸附,这对于Volmer-Heyrovsky步骤至关重要.
- 异构结构中的金属Mo成分对于催化剂性能来说不如表面重建现象那么重要.
- 这些发现指导了用于性水电解剂的稳定和活性碳化物基催化剂的设计.
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