Electronic Modulation Caused by Interfacial Ni‐O‐M (M=Ru, Ir, Pd) Bonding for Accelerating Hydrogen Evolution Kinetics

Abstract

Designing definite metal-support interfacial bond is an effective strategy for optimizing the intrinsic activity of noble metals, but rather challenging. Herein, a series of quantum-sized metal nanoparticles (NPs) anchored on nickel metal-organic framework nanohybrids (M@Ni-MOF, M = Ru, Ir, Pd) are rationally developed through a spontaneous redox strategy. The metal-oxygen bonds between the NPs and Ni-MOF guarantee structural stability and sufficient exposure of the surface active sites. More importantly, such precise interfacial feature can effectively modulate the electronic structure of hybrids through the charge transfer of the formed Ni-O-M bridge and then improves the reaction kinetics. As a result, the representative Ru@Ni-MOF exhibits excellent hydrogen evolution reaction (HER) activity at all pH values, even superior to commercial Pt/C and recent noble-metal catalysts. Theoretical calculations deepen the mechanism understanding of the superior HER performance of Ru@Ni-MOF through the optimized adsorption free energies of water and hydrogen due to the interfacial-bond-induced electron redistribution.

Nitrate‐to‐Ammonia Conversion on Ru/Ni Hydroxide Hybrid through Zinc‐Nitrate Fuel Cell

“…Ru‐25CV/CFP shows FE NH3 to almost 100% at potentials blow 0.1 V versus RHE, with ammonia yield rate ( V NH3 ) of 8.2 × 10 –8 mol s –1 cm –2 at −0.2 V versus RHE as indicated in Figure S4c in the Supporting Information, being consistent with early reports. [ 22 ] When CFP is replaced by NF, HER can be notably improved, as shown in Figure S5a in the Supporting Information and Figure 6a, which is in consistence with recently reported result, [ 32 ] indicating that NF substrate is beneficial to increase the hydrogen supply. As evidenced by the reaction current, Ru‐25CV on NF (Figure 2d and Figure S5c,d, Supporting Information) offers remarkably higher current than that on CFP, which can be further improved through optimizing Ru amounts (Figure S6a,b, Supporting Information) and NO 3 – concentration in the range of 0.01 to 1.0 m (Figure S6c, Supporting Information).…”

“…As the proton are related with the hydrogeneration of NITRR, the ability of proton supply are crucial for achieving high activity. The Ru‐Ni‐O structure has been prove to significantly enhancing the HER performance by our work and recent study, [ 32 ] which accelerates proton supply for hydrogeneration steps of NITRR. Furthermore, oxygen doping in Ru plays a crucial role for nitrate‐to‐ammonia conversion; however, Ru‐O species are likely to be reduced during NITRR, resulting in performance drop as shown on Ru‐25CV/CFP (Figure S9, Supporting Information).…”

“…Ru‐25CV loaded on carbon fiber paper (Ru‐25CV/CFP, as employed by Zhang et al. [ 32 ] ) has been employed for comparison. Compared with blank KOH, the onset potentials Ru‐25CV/CFP (Figure S4, Supporting Information) shifts from −0.05 to 0.15 V versus RHE with NO 3 – addition, indicating excellent response to NITRR.…”

“…Nitrate reduction reaction (NITRR) activity of Ru-25CV/NF catalysts was evaluated by liner scan voltammetry (LSV) and CV measurements in 1.0 m KOH with or without NaNO 3 , as shown in Figure 2d and Figures S4-S8 in the Supporting Information. Ru-25CV loaded on carbon fiber paper (Ru-25CV/CFP, as employed by Zhang et al [32] ) has been employed for comparison. Compared with blank KOH, the onset potentials Ru-25CV/ CFP (Figure S4 consistent with early reports.…”

Nanoporous nickel with rich adsorbed oxygen for efficient alkaline hydrogen evolution electrocatalysis

“…Nanoscale metal catalysts often exhibit different surface nature and catalytic activities from bulk materials [17][18][19], which may provide a good opportunity to study the origin of the difference in alkaline HER activity. In terms of composition design, Ni-based or Ni-containing materials are a highly important class of catalysts with good catalytic activity toward HER [20][21][22][23][24]. High expectations have been placed on the ability of Ni to reduce dependence on precious metals and even completely replace precious metal catalysts.…”