Jana Rajkumar, Bhim Anupam, Bothra Pallavi, Pati Swapan K, Peter Sebastian C
New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore, India.
Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore, India.
ChemSusChem. 2016 Oct 20;9(20):2922-2927. doi: 10.1002/cssc.201601081. Epub 2016 Sep 21.
Manipulating the d-band center of the metal surface and hence optimizing the free energy of hydrogen adsorption (ΔG ) close to the optimal adsorption energy (ΔG =0) for hydrogen evolution reaction (HER), is an efficient strategy to enhance the activity for HER. Herein, we report a oleylamine-mediated (acting as the solvent, stabilizer, and reducing agent) strategy to synthesize intermetallic PdCu nanoparticles (NPs) without using any external reducing agent. Upon electrochemical cycling, PdCu transforms into Pd-rich PdCu (ΔG =0.05 eV), exhibiting remarkably enhanced activity (with a current density of 25 mA cm at ∼69 mV overpotential) as an alternative to Pt for HER. The first-principle calculation suggests that formation of low coordination number Pd active sites alters the d-band center and hence optimal adsorption of hydrogen, leading to enhanced activity. This finding may provide guidelines towards the design and development of Pt-free highly active and robust electrocatalysts.
调控金属表面的d带中心，从而将析氢反应（HER）的氢吸附自由能（ΔG）优化至接近最佳吸附能（ΔG = 0），是提高HER活性的有效策略。在此，我们报道了一种油胺介导的（用作溶剂、稳定剂和还原剂）策略，无需使用任何外部还原剂即可合成金属间化合物PdCu纳米颗粒（NPs）。在电化学循环过程中，PdCu转变为富Pd的PdCu（ΔG = 0.05 eV），作为HER的Pt替代物，其活性显著增强（在约69 mV过电位下电流密度为25 mA cm）。第一性原理计算表明，低配位数Pd活性位点的形成改变了d带中心，进而优化了氢的吸附，导致活性增强。这一发现可能为无Pt高活性和稳健电催化剂的设计与开发提供指导。
