Evolving cost-effective transition metal phosphides (TMPs) using general approaches for energy storage is pivotal but challenging. Besides, the absence of noble metals and high electrocatalytic activity of TMPs allow their applicability as catalysts in oxygen evolution reaction (OER). Herein, CoNiP-CoP 2 (CNP-CP) composite is in situ deposited on carbon fabric by a one-step hydrothermal technique. The CNP-CP reveals hybrid nanoarchitecture (3D-on-1D HNA), i.e., cashew fruit-like nanostructures and nanocones. The CNP-CP HNA electrode delivers higher areal capacity (82.8 𝝁Ah cm -2 ) than the other electrodes. Furthermore, a hybrid cell assembled with CNP-CP HNA shows maximum energy and power densities of 31 𝝁Wh cm -2 and 10.9 mW cm -2 , respectively. Exclusively, the hybrid cell demonstrates remarkable durability over 30 000 cycles. In situ/operando X-ray absorption near-edge structure analysis confirms the reversible changes in valency of Co and Ni elements in CNP-CP material during real-time electrochemical reactions. Besides, a quasi-solid-state device unveils its practicability by powering electronic components. Meanwhile, the CNP-CP HNA verifies its higher OER activity than the other catalysts by revealing lower overpotential (230 mV). Also, it exhibits relatively small Tafel slope (38 mV dec -1 ) and stable OER activity over 24 h. This preparation strategy may initiate the design of advanced TMP-based materials for multifunctional applications.

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Developing cost-effective and catalytically high active noble-metal-free electrocatalysts is of great importance for high-performance and long-durable water electrolysis systems. Herein, nickel–cobalt phosphite (NCP) (M11(HPO3)8(OH)6, M = Ni and Co) microbuds are directly deposited on nickel foam (NF) by a one-step hydrothermal method to serve as an electrocatalyst for oxygen evolution reaction (OER). Owing to high electrochemical activity and good electrokinetics, the NCP material prepared for 5 h of reaction time (NCP-5 h@NF) as the precatalyst demonstrated superior OER activity with an overpotential of only 246 mV to generate a current density of 10 mA cm–2. It also exhibited a lower Tafel slope of 77 mV dec–1. In addition, the NCP-5 h@NF revealed a stable OER activity over 24 h of the chronopotentiometry test. Concurrently, the catalyst surface was reconstructed by transforming its surface into microflowers. Moreover, an anion-exchange membrane water electrolyzer cell (AEMWEC) was fabricated with NCP-5 h@NF as an anode and platinum–carbon as a cathode to explore the capability of the NCP catalyst in an overall water splitting. The AEMWEC not only delivered a high electrolysis performance of 824 mA cm–2 at ∼2 V but also conserved its catalytic activity for 240 h. This new approach promotes the fabrication of cost-effective and noble-metal-free catalysts by one-step methods for durable water electrolysis systems.

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