Bi-functional 3D-NiCu-Double Hydroxide@Partially Etched 3D-NiCu Catalysts for Non-Enzymatic Glucose Detection and the Hydrogen Evolution Reaction

Abstract

Hydrogen production, which is in the spotlight as a promising eco-friendly fuel, and the need for inexpensive and accurate electronic devices in the biochemistry field are important emerging technologies. However, the use of electrocatalytic devices based on expensive noble metal catalysts limits commercial applications. In recent years, to improve performance and reduce cost, electrocatalysts based on cheaper copper or nickel materials have been investigated for the non-enzymatic glucose oxidation reaction (GOR) and hydrogen evolution reaction (HER). In this study, we demonstrate a facile and easy electrochemical method of forming a cheap nickel copper double hydroxide (NiCu-DH) electrocatalyst deposited onto a three-dimensional (3D) CuNi current collector, which can effectively handle two different reactions due to its high activity for both the GOR and the HER. The as-prepared electrode has a structure comprising abundant 3D-interconnected porous dendritic walls for easy access of the electrolyte ions and highly conductive networks for fast electron transfer; additionally, it provides numerous electroactive sites. The synergistic combination of the dendritic 3D-CuNi with its abundant active sites and the self-made NiCu-DH with its excellent electrocatalytic activity toward the oxidation of glucose and HER enables use of the catalyst for both reactions. The as-prepared electrode as a glucose sensor exhibits an outstanding glucose detection limit value (0.4 μM) and a wide detection range (from 0.4 μM to 1.4 mM) with an excellent sensitivity of 1452.5 μA/cm2/mM. The electrode is independent of the oxygen content and free from chloride poisoning. Furthermore, the as-prepared electrode also requires a low overpotential of −180 mV versus reversible hydrogen electrode to yield a current density of 10 mA/cm2 with a Tafel slope of 73 mV/dec for the HER. Based on this performance, this work introduces a new paradigm for exploring cost-effective bi-functional catalysts for the GOR and HER.

A Nickel-Doped Two-Dimensional Covalent Organic Polymer (2D-COP) for Electrocatalytic Hydrogen Evolution Reaction

“…The XPS survey spectrum of Ni@COP demonstrates the proximity of C, O, N, S, and Ni elements, which further confirms the purity of the material (Figure a). The high-resolution XPS (HR-XPS) C 1s spectrum provides four distinct deconvoluted peaks at 284.4 eV, 286.1 eV, 286.3 eV, and 288.0 eV that correlate with the bonding interactions of C–S–C, −C­(O)­N, −CN, and −CO of imine groups (Figure b). − Additionally, an extra peak at 291.8 eV was observed for C 1s spectrum, attributed to the presence of −CF 2 functional groups of the Nafion binder. , The HR-XPS N 1s spectrum shows two prominent peaks located at 399.8 and 401.9 eV, representing −CN and −N–N bonds in the Ni@COP (Figure c) . The HR-XPS O 1s spectrum shows four prominent signals at 532.2, 533.4, 535.2, and 530.8 eV, which were attributed to the C–O, C–OH, −O–F x -, and CO bonds, respectively (Figure d). , The HR-XPS S 2p spectrum (Figure e) exhibits two prominent signals at 168.7 and 169.7 eV, indicating the presence of SO 3 2– group in the COP moiety .…”

“…According to the previously reported metal-based electrocatalyst, the Ni-doped COP shows comparable catalytic activity (Table S2). − To get deeper insight into the electron transport kinetics, an EIS measurement was performed. Figure c,d shows the Nyquist plots fitted to the equivalence circuit model to determine the charge transfer resistance ( R ct ) of the Ni@COP, 10% Pt/C, COP, Ni­(NO 3 ) 2 ·6H 2 O, and CP electrode.…”

“…53,54 The HR-XPS N 1s spectrum shows two prominent peaks located at 399.8 and 401.9 eV, representing −C�N and −N−N bonds in the Ni@COP (Figure 2c). 57 The HR-XPS O 1s spectrum shows four prominent signals at 532.2, 533.4, 535.2, and 530.8 eV, which were attributed to the C−O, C−OH, −O−F x -, and C�O bonds, respectively (Figure 2d). 50,51 The HR-XPS S 2p spectrum (Figure 2e) exhibits two prominent signals at 168.7 and 169.7 eV, 47 indicating the presence of SO 3 2− group in the COP moiety.…”

Hydrogen co-production via nickel-gold electrocatalysis of water and formaldehyde

“… 13 They can be converted into valuable organic backbones rather than oxygen, 14 avoiding the coexistence of hydrogen and oxygen while balancing the initial resource investment. 15 , 16 The concept has been validated in the iteratively upgraded platform for the electrolysis of biomass-derived chemicals such as glucose, 17 furfural, 1 and similar small molecules. 18 , 19 , 20 , 21 , 22 However, a high-voltage input is often necessary (> 1 V vs. RHE), 14 , 23 , 24 and the organic compounds commonly face solubility issues in a water medium, limiting scaled-up H 2 production.…”

A Comparison between Porous to Fully Dense Electrodeposited CuNi Films: Insights on Electrochemical Performance

“…Among metallic alloys, the Cu-Ni system has sparked the attention of researchers owning to its good electrocatalytic activities towards HER and its key roles in various electrochemical processes [ 25 , 26 , 27 ]. Typically, bimetallic CuNi materials show enhanced electrocatalytic activity and selectivity compared to monometallic Ni [ 28 , 29 ].…”