Efficient Water Splitting Using a Simple Ni/N/C Paper Electrocatalyst

Abstract

An efficient water splitting electrocatalyst is presented. Cheap and sustainable cellulose filter paper, infiltrated with nickel acetate as the nickel source, and phenanthroline as a ligand and nitrogen source are carbonized together. Nitrogen functionalities turn out to be crucial coordination sites for the supported Ni/NiO(OH) particles. This simple and scalable one step procedure leads to powders, but also to complete membranes made of ≈10 wt% Ni, supported on nitrogen functionalized carbon. The non‐noble catalyst shows a low onset potential (330 mV vs reversible hydrogen electrode), high current density (e.g., j > 25 mA cm−­2 at η = 430 mV), excellent kinetics (Tafel slope of 44 mV dec−1), and a very favorable stability (<5% decay after 10 h electrolysis) in the oxygen evolution. The performance is similar or even better compared to state‐of‐the‐art noble metal catalysts (e.g., IrO2, Ir/C, Ru/C, and Pt/C). Because of the simple, cheap, and scalable preparation procedure the catalyst is highly promising for practical low price/tech applications. Interestingly, the system is also active in the hydrogen evolution reaction, leading to a promising bifunctional catalyst. The benchmark characteristics are η10 = 390 mV for oxygen evolution and η10 = 190 mV for hydrogen evolution, that is, an overall efficiency of 68% at 10 mA current density.

General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities

“…34). To put it into context, the η 10 value of Ni-NHGF is superior or comparable to most of the documented nanoparticulate Ni catalysts, such as Ni/NiO(OH) particles embedded in nitrogen functionalized carbon (390 mV) 52 , nickel vanadium layered double hydroxide (NiV-LDH) (318 mV) 53 , exfoliated NiCo-LDH (334 mV) 54 , NiCoO x thin film (380 mV) 55 , and nickel carbide on conductive carbon (Ni 3 C/C) (316 mV) 56 …”

In Situ Coupling Strategy for the Preparation of FeCo Alloys and Co4N Hybrid for Highly Efficient Oxygen Evolution

“…The obtained Tafel slope of FeCo-Co 4 N/N-C (40 mV dec −1 ) is lower than that of RuO 2 (86 mV dec −1 ) and NiCo-UMOFNs (42 mV dec −1 ), [11] suggesting favorable reaction kinetics, which could be attributed to the intrinsic mesoporous structure that efficiently liberating gas bubbles. [36] A more detailed investigation of the reaction mechanism, using the rotating ring-disk electrode (RRDE) technique with a Pt ring electrode potential of 1.50 V (RHE), was carefully performed. [4] Under this condition, the peroxide intermediates generated at the FeCo-Co 4 N/N-C surface during the OER can be oxidized.…”

Amorphous Cobalt Boride (Co2B) as a Highly Efficient Nonprecious Catalyst for Electrochemical Water Splitting: Oxygen and Hydrogen Evolution

“…[ 1,2 ] The state-of-the art catalysts for the oxygen evolution reaction (OER), the anode reaction during water electrolysis, are typically RuO 2 and IrO 2 , [3][4][5][6] while platinum-based alloys are used at the cathode for the hydrogen evolution reaction (HER). However, to date, no catalysts exist that combine cost effectiveness, high performance, and long-term durability, which impedes the competitiveness of large-scale hydrogen and oxygen production through electrochemical water splitting.…”

“…[ 5,7 ] Owing to the scarcity and high cost of precious metals, vigorous efforts have been pursued to develop lowcost and readily available electrocatalysts for water splitting. [ 2,[16][17][18][19] Intriguingly, these materials also exhibit exceptionally good activity towards hydrogen evolution, [ 20 ] which essentially unveils "a new chemistry" of materials for water splitting. [ 10 ] Although RuO 2 and IrO 2 still command superior performance for OER in acidic electrolytes, recent studies have reported tremendous improvement of OER catalyzed by nonprecious catalysts in alkaline electrolytes with activity and stability benchmarks surpassing RuO 2 and IrO 2 by incorporating a non-metal element (e.g., N, S, P, Se) in the oxide, or hydroxide structure of cobalt [11][12][13][14][15] or nickel.…”