Echinops‐like bimetallic CoNiP−CoNi alloy is synthesized from a metal−organic framework (MOF) and serves as an efficient catalyst for the oxygen evolution reaction (OER), with a low overpotential of 300 mV in 1 M KOH at 10 mA cm−2 (η10). The cooperative effect of Ni and Co metal, as well as the interfacial properties of the integrated semiconducting phosphide/metallic alloy and electronic conductivity of the MOF‐derived carbon regulate the performance of the catalyst. Moreover, the bimetallic CoNiP/CoNi alloy catalyst is interspersed with N‐doped graphene, forming a triad catalyst that demonstrates superior activity towards the hydrogen evolution reaction (η10=150 mV) and excellent durability, owing to interfacial effects of the triad catalyst, large electrochemical active surface area, and enhanced conductivity from N‐doped graphene. The stability of the carbon‐containing catalyst during OER (oxidation) is altered by the high reactivity of heteroatom dopant. The assembled CoNiP/CoNi/N−RGO||CoNiP/CoNi water electrolyzer delivers a reasonable cell potential of 1.76 V at 10 mA cm−2. The synthesized bimetallic CoNiP/CoNi alloy‐based triad catalyst thus demonstrates excellent electrocatalytic activity and high durability suitable for efficient alkaline water splitting.

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Polypyrrole (PPy)/cellulose (PPCL) composite papers were fabricated by vapor phase polymerization. Importantly, the vapor-phase deposition of PPy onto cellulose was assisted by employing different co-vapors namely methanol, ethanol, benzene, water, toluene and hexane, in addition to pyrrole. The resulting PPCL papers possessed high mechanical flexibility, large surface-to-volume ratio, and good redox properties. Their main properties were highly influenced by the nature of the co-vaporized solvent. The morphology and oxidation level of deposited PPy were tuned by employing co-vapors during the polymerization, which in turn led to change in the electrochemical properties of the PPCL papers. When methanol and ethanol were used as co-vapors, the conductivities of PPCL papers were found to have improved five times, which was likely due to the enhanced orientation of PPy chain by the polar co-vapors with high dipole moment. The specific capacitance of PPCL papers obtained using benzene, toluene, water and hexane co-vapors was higher than those of the others, which is attributed to the enlarged effective surface area of the electrode material. The results indicate that the judicious choice and combination of co-vapors in vapor-deposition polymerization (VDP) offers the possibility of tuning the morphological, electrical, and electrochemical properties of deposited conducting polymers.

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Owing to their high catalytic activity, transition metal hydroxides are promising electrocatalysts for non-enzymatic glucose sensors. The hydroxyl functionalities in Co 1−x Ni x hydroxide/mixed anionic hydroxides play a vital role in their electrochemical activation via conversion to an oxyhydroxide catalyst and thus impact their sensitivity to small molecule (glucose) oxidation. Herein, we report the rational synthesis of M 2 (OH) 4−n (A n− ) compositions (0 > n ≤ 2) with hydroxide (OH)rich and OH-deficient phases, viz., CoNi-hydroxide nitrate (CoNi-HN) and CoNi-hydroxide carbonate (CoNi-HC), by using different solvents of ethanol and water, under solvo/hydrothermal conditions, respectively. The OH-rich CoNi-HN phase exhibited enhanced pre-activation efficiency, which accelerated the glucose oxidation kinetics, and beneficial morphological features (flowerlike structures with interconnected nanosheets). The OH-rich CoNi-HN catalyst, which is the first report for a glucose sensor, exhibited superior sensing property with a high sensitivity of ∼136 μA mM −1 cm −2 . The structure−(sensing) property relationship was analyzed in detail by tailoring the morphology to form an OH-rich graphene oxide (GO) hybrid. The CoNi-HN/GO hybrid exhibited improved glucose oxidation, delivering a wide glucose-sensing range, with a sensitivity of ∼268 μA mM −1 cm −2 , a low detection limit of 28.5 μM (S/N = 3), and good selectivity. The excellent sensitivity of this hybrid was attributed to the synergism between the OH-rich CoNi-HN phase and the OH-rich interfaces between GO and CoNi-HN, as well as a unique flower-like morphology with interconnected nanosheets. Insights into the critical role of hydroxyl groups in the electrocatalytic performance of transition-metal-based catalysts have been emphasized in this work.

Developing oxygen evolution reaction (OER) catalysts is intricate and challenging, involving a four-electron transport process coupled with conversion of O−H bonds into O− O bonds. This paper proposes a simple one-step synthetic strategy for preparing self-supported Cu 2 Se/NiSe 2 heteronanostructure electrodes for the OER with well-defined heterointerfaces by directly embedding onto the conductive nickel foam substrate. The prepared catalyst significantly enhances OER activity with low overpotentials of 277 and 290 mV at current densities of 50 and 100 mA cm −2 , respectively, which is attributed to electronic structure modulation by synergetic interactions and enhanced charge transportation between Cu 2 Se and NiSe 2 nanostructures. The as-prepared electrodes achieved high durability in 1 M KOH, retaining initial activity levels after 24 h continuous operation. We performed comprehensive spectroscopic and microscopic characterization before and after the OER to clarify active species and relate them to OER catalysis. Enhanced catalyst efficiency arises from integrating multicomponent electrocatalytic systems, which has been emphasized by the present findings.