A porous N-doped carbon-encapsulated CoNi alloy nanoparticle composite (CoNi@N−C) was prepared using a bimetallic metal−organic framework composite as the precursor. The optimal prepared Co 1 Ni 1 @N−C material at 800 °C exhibited well-defined porosities, uniform CoNi alloy nanoparticle dispersion, a high doped-N level, and scattered CoNi−N x active sites, therefore affording excellent oxygen catalytic activities toward the reduction and evolution processes of oxygen. The oxygen reduction (ORR) onset potential (E onset ) on Co 1 Ni 1 @N−C was 0.91 V and the halfwave potential (E 1/2 ) was 0.82 V, very close to the parameters recorded on the Pt/C (20 wt Pt%) benchmark. Moreover, it is worth noting that the ORR stability of Co 1 Ni 1 @N−C was prominently higher than that of Pt/C. Under the oxygen evolution reaction condition, Co 1 Ni 1 @N−C generated the maximum current density at the potential of 1.7 V (8.60 mA cm −2 ) and the earliest E onset (1.35 V) among all Co x Ni y @N−C hybrids. The Co 1 Ni 1 @N−C catalyst exhibited the smallest ΔE value, confirming the superior bifunctional activity. The high surface area and porosity, and CoNi−N x active sites on the carbon surface including the proper interactions between the N-doped C shell and CoNi nanoparticles were attributed as the main contributors to the outstanding oxygen electrocatalytic property and good stability.
By adjusting various Ru/M (M=Co, Ni) molar ratios, a series of highly dispersed bimetallic RuM alloy nanoparticles (NPs) anchored on MIL-110(Al) have been successfully prepared via a conventional impregnation-reduction method. And they are first used as heterogeneous catalysts for the dehydrogenation reaction of AB at room temperature. The results reveal that the as-prepared Ru 1 Co 1 @MIL-110 and Ru 1 Ni 1 @MIL-110 exhibit the highest catalytic activities in different RuCo and RuNi molar ratios, respectively. It is worthy of note that the turnover frequency (TOF) values of Ru 1 Co 1 @MIL-110 and Ru 1 Ni 1 @MIL-110 catalysts reached 488.1 and 417.1 mol H 2 min −1 (mol Ru) −1 and the activation energies (E a) are 31.7 and 36.0 kJ/mol, respectively. The superior catalytic performance is attributed to the bimetallic synergistic action between Ru and M, uniform distribution of metal NPs as well as bi-functional effect between RuM alloy NPs and MIL-110. Moreover, these catalysts exhibit favorable stability after 5 consecutive cycles for the hydrolysis of AB.
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