Platinum-based bimetallic catalysts exhibit superior hydrogen evolution reaction performance compared to single platinum catalysts. Most studies on platinum bimetallic catalysts have focused on changing the metals used, with not much attention on how the d-band theory affects the catalyst's performance. Herein, we investigated the additional of different transition metals alters the d-band center for better hydrogen evolution. A method combining the ultrasound processing and in-situ reduction was designed, resulting in the alloys with different stacking orders. As the d-band of transition metal elements in the alloy shifts upwards, the lower the energy of the alloy's d-band center, the better the stability of the adsorption bonding exhibited by the alloy. The PtCu/C, with a hexagonal-close-packed structure and a d-band center at −1.823 eV, has an 84 mV overpotential at 100 mA cm −2 , lower than PtNi/C (89 mV) and PtCo/C (91 mV). It also has 4.75 times the mass activity of commercial Pt/C. As a cathode catalyst, PtCu/C provides improved water-splitting at 2.31 V vs. 2.55 V for commercial Pt/C (at 1 A cm −2 ). This analytical strategy through the d-band center advances the design of platinum-based bimetallic catalysts and offers a new direction for the optimization and development of hydrogen evolution reaction electrocatalysts.
The frequently used chloroplatinic acid or other Pt precursors containing Cl element during the preparation process of Pt-based catalysts lead to catalyst poisoning and instability. In this work, a chlorine-free PtCu(N)/C R-F catalyst with a hollow sphere structure was successfully synthesized by employing [Pt(NH 3 ) 4 ](OH) 2 and [Cu(NH 3 ) 4 ](OH) 2 as the chlorine-free metal precursors, which using the strong electrostatic adsorption (SEA) between positively charged metal precursor ions and the negatively charged oxygen-containing functional groups (OCFGs) on the carbon support (C R-F ) and combined with the impregnation reduction method. Compared to commercial Pt/C, the experimental results show that the PtCu(N)/C R-F catalyst, displays better ORR performance under acidic condition, the onset and half-wave potentials are 0.961 V (vs. RHE) and 0.827 V (vs. RHE), respectively. Furthermore, it also shows a significant performance advantage in a gas diffusion electrode (GDE) half-cell. Density-functional theory (DFT) calculations show that the introduction of Cu has adjusted the electronic structure of Pt, weakened the adsorption of oxygen-containing intermediates, and ultimately enhanced the catalytic activity and stability of ORR. This work presents a simple and efficient method for preparing chlorine-free Pt-based catalysts.
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