Search

A non‐precious metal‐based catalyst for water electrolysis provides great promise for cost‐effective and highly efficient sustainable hydrogen production. It herein rationally synthesizes uniform superminiature CoNi nanoparticles (2.6 nm) embedded in 3D N‐doped randomly oriented and erected porous carbon nanosheets (CoNi@N‐PCNS). Taking advantage of the large specific surface area, expedited intermediate transport, and effectively exposed active sites of the hierarchical architecture, located CoNi nanoparticles yield a high atom utilization efficiency. Density functional theory calculations indicate that synergetic and cooperative interactions inside CoNi alloy modulate the d‐band center, leading to a moderate adsorption and desorption energy of reaction intermediates, further accelerating both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics. Accordingly, the as‐synthesized CoNi@N‐PCNS catalyst establishes superb catalytic activities for HER and OER, revealing overpotentials of 71.2 and 263.8 mV at 10 mA cm−2, respectively. Remarkably, when assembled as a two‐electrode electrolyzer, a satisfying cell voltage of 1.59 V at 10 mA cm−2, and superior stability are demonstrated, highlighting great promise toward water electrolysis. [ABSTRACT FROM AUTHOR]

The simultaneous integration of electronic regulation and architectural engineering in one electrocatalyst represents a powerful leverage to concurrently boost the electrocatalytic performance towards overall water splitting. We herein rationally fabricate Sn 4 P 3 /Co 2 P "stalk"-"cap"-typed nanoarrays (Sn 4 P 3 /Co 2 P SCNAs) with abundant heterointerfaces and elaborately implanted "caps". The nanoarrayed structure can substantially enlarge the exposure of active sites and promote the mass/electron transport, thus accelerating the reaction kinetics. Moreover, the purposely grafted "caps" are beneficial to increase the hydrophilicity/aerophobicity, which facilitate the water affinity and release of generated gas bubbles. Accordingly, the obtained Sn 4 P 3 /Co 2 P SCNAs deliver exceptional electrocatalytic performances towards the HER and OER, as reflected by the overpotentials of 45.4 and 280.4 mV at 10 mA cm−2, respectively. More impressively, the two-electrode electrolyzer assembled by freestanding Sn 4 P 3 /Co 2 P SCNAs requires a cell voltage of 1.56 V at 10 mA cm−2 and exhibits superior stability and full reversibility, holding great potential in practical water electrolysis. [Display omitted] • Heterostructured Sn 4 P 3 /Co 2 P SCNAs ("stalk"-"cap"-typed nanoarrays) are fabricated. • Sn 4 P 3 /Co 2 P SCNAs possess regulated electronic structure and increased active sites. • The hydrophilicity/aerophobicity of Sn 4 P 3 /Co 2 P SCNAs benefit gas-releasing reactions. • Sn 4 P 3 /Co 2 P SCNAs exhibit robust electrocatalytic performance and full reversibility. [ABSTRACT FROM AUTHOR]

• A novel sprout-shaped Mo-doped CoP (CP) is prepared via template-assisted method. • CP exhibits excellent catalytic performance and long-term durability. • CP possesses maximized hydrophilicity and efficient gas bubble release. The electrochemical water splitting reaction offers an attractive approach to generate hydrogen fuels as green and renewable energy, in helping ease the global warming and energy crisis, working as a clean energy carrier. In this study, we present the sprout-shaped Mo-doped CoP (denoted CP) as a catalyst for efficient water splitting electrode under alkaline environment. The electrode possesses a unique nanoarray type 'pillar' and microscale 'tip' structure, which promotes high hydrophilicity and effective gas bubble release, hence achieving a future goal of highly efficient water splitting device for practical use. For both hydrogen and oxygen evolution reaction (HER and OER), the electrode shows remarkable catalytic activity together with reliable stability in alkaline solution, which makes CP a promising electrocatalyst to date. By investigating the gas releasing efficiency regarding various nano/microstructured electrodes, as-prepared CP surpasses the compared samples, indicating maximized nano/microstructures specialized for gas evolution electrode. When the CP performed as an overall water splitting electrode, only 1.49 V of overpotential is needed to achieve the current density of 10 mA·cm−2 and maintained 10 and 200 mA·cm−2 for over 35 h with little degradation of catalytic activity. This work would give inspiration to many investigators who work on optimizing structures of transition metal-based nanomaterials, promoting their applications in other renewable energy options. [ABSTRACT FROM AUTHOR]

• Optimization of copper-based electrocatalyst is explored via structure and composition modulation. • Urchin-shaped CuFeMOFs are obtained in aqueous medium via rapid microwave-assisted synthesis. • The urchin-shaped CuFeMOF derived CuFeN/CNT catalyst shows greatly enhanced catalytic property. • The all-microwave-assisted preparation process minimizes use of toxic solvent and excessive energy. Most reported non-precious-metal catalysts for oxygen evolution reaction (OER) are composed of iron, cobalt, or nickel. Copper, on the other hand, is relatively neglected despite its versatility. In this paper, we describe a series of steps to enhance the OER efficiency of copper-based catalyst, including metal organic framework (MOF)-guided structure control, secondary metal doping, and nitridation. In particular, the effect of growth solvent on coordination kinetics and morphology of the precursor MOFs was studied in detail. The optimal MOF structure was further engineered with Fe doping followed by rapid microwave-assisted nitridation, resulting in CuFeN/CNT composite. Experimental results showed that all three engineering steps have significant impact on the enhanced OER efficiency. CuFeN/CNT composite with optimal Fe doping derived from urchin-shaped CuFeMOF exhibited a greatly enhanced OER performance comparable to that of precious metal catalyst, affording a current density as high as 236.3 mA at an overpotential of 420 mV (RuO 2, 215.3 mA). Furthermore, excellent stability in alkaline media was observed during 1000 cycles and chronopotentiometric analysis for over 20 hours. We highlight that the entire synthesis protocol is environmentally benign and sustainable by employing microwave to enable rapid formation and conversion of the precursors with minimal energy consumption. [Display omitted] [ABSTRACT FROM AUTHOR]