Crystallinity Effect of NiFe LDH on the Growth of Pt Nanoparticles and Hydrogen Evolution Performance

Abstract

NiFe layered double hydroxides (LDHs) usually exhibit high waterdissociation ability in the alkaline media and also provide an ideal substrate for anchoring noble metals, such as platinum (Pt), due to the 2D microstructure. Appropriate regulation of the interaction between Pt and substrate could enhance the intrinsic activity of composite catalysts toward the hydrogen evolution reaction (HER) in the alkaline media. Herein, we electrodeposit Pt nanoparticles on amorphous NiFe LDH (Pt/NiFe-ED) or crystalline NiFe LDH (Pt/NiFe-HD) to regulate the interaction between Pt and NiFe LDH. Experimental results reveal that Pt nanoparticles on NiFe-ED are smaller than those on NiFe-HD and possess a narrower size distribution. Thus, Pt/NiFe-ED (300 μM) exhibits a much lower overpotential of 81 mV at 100 mA cm −2 than Pt/NiFe-HD. In contrast, Pt/NiFe-HD exhibits a higher intrinsic activity than Pt/NiFe-ED, which could be caused by the easily elongated Pt−O bond. These findings provide new opportunities to understand the relationship between activity and crystallinity of substrates in the composite electrocatalyst.

Surface Engineering of Cr-Doped Cobalt Molybdate toward High-Performance Hydrogen Evolution

“…According to the corresponding Tafel plots diagram (Figures c and S12c), the Tafel slope of CoMoO 4 (147.5 mV dec –1 ), Cr-CoMoO 4 (129.6 mV dec –1 ), and E-CoMoO 4 (158.4 mV dec –1 ) is greater than 120 mV dec –1 , demonstrating that the Volmer step is the rate-determining step. The Tafel slope of PE-Cr-CoMoO 4 is only 71.5 mV dec –1 , obviously lower than that of other comparative samples, showing fast reaction kinetics and conforming to the Volmer–Heyrovsky mechanism. , …”

“…To evaluate the HER activity, we first evaluated the electrocatalytic performance of the synthesized PE-Cr- showing fast reaction kinetics and conforming to the Volmer− Heyrovsky mechanism. 31,32 Additionally, EIS analysis was used to investigate the intrinsic kinetic behavior of the catalysts. We compared the intrinsic electron transfer of the samples by fitting the measured EIS data with the circuits in Figure S13 to obtain R s and R ct .…”

Heterointerface engineering constructs microenvironment enhancing catalytic kinetics of Fe/Ni oxyhydroxide@FeNi alloy for overall water splitting

“…S5, ESI†) to obtain the capacitive double layer ( C dl ) and to clarify the surface area. 4,26,27 The C dl value was obtained from the slope of plotting scan rates vs current density, as shown in Fig. 4d.…”

A nitridation route to construct high-activity interfaces toward alkaline hydrogen evolution

“…To solve these problems, it is indispensable to optimize the interfacial structure by modulating the electron transfer to enhance the HER catalytic performance. Various strategies, including forming covalent structures with strong interaction between metal and non-metal, [17][18][19] interfacial engineering (heterostructures), [20][21][22] and phase transition, have been proposed to regulate the interfacial electron transfer. 23 One of the main problems among these strategies involves their complicated (NPNNS) as an efficient electrocatalyst for HER in neutral, alkaline and acidic media, which could be ascribed to "metalmetal interaction" and "hybridization" promoting exible electron transfer between the two parts.…”