Superaerophobic Ultrathin Ni–Mo Alloy Nanosheet Array from In Situ Topotactic Reduction for Hydrogen Evolution Reaction

Abstract

Hydrogen evolution reaction (HER) has prospect to becoming clean and renewable technology for hydrogen production and Ni-Mo alloy is among the best HER catalysts in alkaline electrolytes. Here, an in situ topotactic reduction method to synthesize ultrathin 2D Ni-Mo alloy nanosheets for electrocatalytic hydrogen evolution is reported. Due to its ultrathin structure and tailored composition, the as-synthesized Ni-Mo alloy shows an overpotential of 35 mV to reach a current density of 10 mA cm , along with a Tafel slope of 45 mV decade , demonstrating a comparable intrinsic activity to state-of-art commercial Pt/C catalyst. Besides, the vertically aligned assemble structure of the 2D NiMo nanosheets on conductive substrate makes the electrode "superaerophobic," thus leading to much faster bubble releasing during HER process and therefore shows faster mass transfer behavior at high current density as compared with drop drying Pt/C catalyst on the same substrate. Such in situ topotactic conversion finds a way to design and fabricate low-cost, earth-abundant non-noble metal based ultrathin 2D nanostructures for electrocatalytic issues.

Self‐Supporting Ni‐M (M = Mo, Ge, Sn) Alloy Nanosheets via Topotactic Transformation of Oxometallate Intercalated Layered Nickel Hydroxide Salts: Synthesis and Application for Electrocatalytic Hydrogen Evolution Reaction

“…The intrinsic catalytic activity is evaluated by turnover frequency (TOF), calculated by normalizing the HER activity to the number of active sites (Figure S16, Supporting Information). The TOF of Ni 4 Mo/NF is 0.8 s −1 at the overpotential of 87.0 mV, close to that of Pt/C . These findings indicate that both high intrinsic activity of Ni 4 Mo sites and large ECSA of the self‐supporting Ni 4 Mo nanosheets on nickel foam contribute to the measured superior HER activity.…”

Recent Advances in Non‐Precious Metal‐Based Electrodes for Alkaline Water Electrolysis

“…The material was prepared by in-situ topotactic reduction at a relatively low-temperature ( Figure 2C). [23] This NiMo alloy nanosheet array demonstrated overpotential of À 35 mV at À 10 mA cm À 2 in 1.0 M KOH, while outperforming the noble Pt/C in terms of higher current density values ( Figure 2D). The use of Ni-catalyst has been projected using various route.…”

“…In a similar content, we also reported the use of ultrathin NiMo alloy nanosheet for enhanced HER activity. The material was prepared by in‐situ topotactic reduction at a relatively low‐temperature (Figure C) . This NiMo alloy nanosheet array demonstrated overpotential of −35 mV at −10 mA cm −2 in 1.0 M KOH, while outperforming the noble Pt/C in terms of higher current density values (Figure D).…”

Network‐Like Ni1−xMox Nanosheets: Multi‐Functional Electrodes for Overall Water Splitting and Supercapacitor

“…In the HRXPS spectra of Mo 3d (Figure 2d), the peaks at 228.2 � 0.2 eV, 229.2 � 0.2 eV, 230.3 � 0.2 eV, and 232.3 � 0.2 eV eV are indexed to Mo 0 , Mo + 4 , Mo + 5 , and Mo + 6 , respectively. [57][58][59] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 [57][58][59] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 …”