Vertically Aligned Metal–Organic Framework Derived from Sacrificial Cobalt Nanowire Template Interconnected with Nickel Foam Supported Selenite Network as an Integrated 3D Electrode for Overall Water Splitting

Abstract

The development of bifunctional, highly active electrocatalysts for an overall water splitting reaction remains a major challenge. Here, the sacrificial template-assisted transformation of cobalt hydroxide nanowire (Co(OH) 2 NW) into a metal−organic framework network (MOF) is conceived as a porous structure that provides extremely active and durable electrochemical energy conversion characteristics. After this, the 1D MOF modified Co NWs can be further transformed into a hybrid structure (MOF CoSeO 3 NWs) by selenization. The self-template transformation strategy allows the interconnected porous conductive network to be exposed to abundant reactive sites and to improve electronic conductivity/structural integrity. Thus, the obtained catalyst established by electrocatalytic activity in the course of the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) in 1 M KOH solution requires overpotentials (η) of 290 and 150 mV to achieve a current density of 50 and 10 mA cm −2 for both OER and HER. Interestingly, as a full cell water electrolyzer (MOF CoSeO 3 NWs (+) // MOF CoSeO 3 NWs (−)), the MOF CoSeO 3 NW's modified electrode exhibits an affordable cell voltage of 1.675 V at a current density of 100 mA cm −2 . This work involves a viable and systematic strategy to prepare many other functional integrated MOFs that can be used for energy storage and conversion in multiple applications.

Highly Oriented Nitrogen‐doped Carbon Nanotube Integrated Bimetallic Cobalt Copper Organic Framework for Non‐enzymatic Electrochemical Glucose and Hydrogen Peroxide Sensor

“…For comparison, MOF Co, MOF Cu, and MOF CoCu nanocubes were also performed. As can be seen in Figure 3A, the XRD pattern of MOF Co (a) and MOF Cu (b) is exactly matched with our previous report [34, 35]. Figure 3A (c) shows the XRD pattern of MOF CoCu nanocubes with several peaks at 2θ of about 7.16, 10.2, 12.6, 14.4, 16.3, 17.9, 22.0, 24.5, 26.6, 29.6, 31.2, and 32.3° associated with (011), (022), (112), (022), (013), (222), (114), (233), (134), (044), (244), and (235) diffraction planes of MOF Co [35].…”

“…As can be seen in Figure 3A, the XRD pattern of MOF Co (a) and MOF Cu (b) is exactly matched with our previous report [34, 35]. Figure 3A (c) shows the XRD pattern of MOF CoCu nanocubes with several peaks at 2θ of about 7.16, 10.2, 12.6, 14.4, 16.3, 17.9, 22.0, 24.5, 26.6, 29.6, 31.2, and 32.3° associated with (011), (022), (112), (022), (013), (222), (114), (233), (134), (044), (244), and (235) diffraction planes of MOF Co [35]. The MOF CoCu nanocubes XRD pattern is identical to that of MOF Co suggesting that the presence of copper has a marginal impact on the crystallinity [36].…”

“…As can be seen in Figure 3A, the XRD pattern of MOF Co (a) and MOF Cu (b) is exactly matched with our previous report [34,35]. 022), ( 112), ( 022), ( 013), ( 222), ( 114), ( 233), ( 134), ( 044), (244), and (235) diffraction planes of MOF Co [35]. The MOF CoCu nanocubes XRD pattern is identical to that of MOF Co suggesting that the presence of copper has a marginal impact on the crystallinity [36].…”

“…For comparison, MOF Co, MOF Cu, and MOF CoCu nanocubes were also performed. As can be seen in Figure 3A, the XRD pattern of MOF Co (a) and MOF Cu (b) is exactly matched with our previous report [34,35]. 022), ( 112), ( 022), ( 013), ( 222), ( 114), ( 233), ( 134), ( 044), (244), and (235) diffraction planes of MOF Co [35].…”

Simple Construction of Amorphous Monometallic Cobalt‐Based Selenite Nanoparticles using Ball Milling for Highly Efficient Oxygen Evolution Reaction

“…However, it was found that the peak of SeO x at 58.5 eV has some shift in the Se 3d spectrum (Figure 3c), [26,37,38] approximately a positive shift of 0.66 eV compared with that of the crystalline C 4 S sample, revealing the increase of low‐coordination Se content, which could be attributed to probable existence of Se vacancies in the amorphous C 4 S‐12 h material, which would facilitate the enhanced OER performance [39–40] . Correspondingly, it could be seen that the Se−O−M peak around 530.7 eV [41–42] in the O 1s high‐spectrum (Figure 3d) also has an obvious high‐energy shift. Thus, the electronic structure of this amorphous material could be changed by this mechanical ball milling method.…”