RuNi Nanoparticles Embedded in N‐Doped Carbon Nanofibers as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting

Abstract

Developing high‐performance, low‐cost, and robust bifunctional electrocatalysts for overall water splitting is extremely indispensable and challenging. It is a promising strategy to couple highly active precious metals with transition metals as efficient electrocatalysts, which can not only effectively reduce the cost of the preparation procedure, but also greatly improve the performance of catalysts through a synergistic effect. Herein, Ru and Ni nanoparticles embedded within nitrogen‐doped carbon nanofibers (RuNi‐NCNFs) are synthesized via a simple electrospinning technology with a subsequent carbonization process. The as‐formed RuNi‐NCNFs represent excellent Pt‐like electrocatalytic activity for the hydrogen evolution reaction (HER) in both alkaline and acidic conditions. Furthermore, the RuNi‐NCNFs also exhibit an outstanding oxygen evolution reaction (OER) activity with an overpotential of 290 mV to achieve a current density of 10 mA cm−2 in alkaline electrolyte. Strikingly, owing to both the HER and OER performance, an electrolyzer with RuNi‐NCNFs as both the anode and cathode catalysts requires only a cell voltage of 1.564 V to drive a current density of 10 mA cm−2 in an alkaline medium, which is lower than the benchmark of Pt/C||RuO2 electrodes. This study opens a novel avenue toward the exploration of high efficient but low‐cost electrocatalysts for overall water splitting.

Structural design toward functional materials by electrospinning: A review

“…By structural design with modifications on spinnerets and collectors, functional electrospun fibers with special structures Janus, core-shell, hollow, porous, helical, etc., are comprehensively investigated. Such functional electrospun fibers have been widely used in different fields, such as masks (26,27), stimuli-responsive materials and actuators (28)(29)(30)(31), separation and filtration (32)(33)(34)(35)(36)(37)(38)(39), reinforcements (40)(41)(42)(43)(44)(45), wearable electronics (46)(47)(48)(49)(50), sponges/aerogels (51)(52)(53)(54)(55)(56), tissue engineering (57,58), detection metal ions (59)(60)(61), energy storage (62)(63)(64)(65)(66), catalysts (67)(68)(69)(70)(71)(72)…”

Electrospun Inorganic Nanofibers for Oxygen Electrocatalysis: Design, Fabrication, and Progress

“…Additionally, a low cell voltage of 1.57 V at 10 mA cm −2 in water electrolysis measurement was obtained, without noticeable decay after 27 h, suggesting excellent performance of Ni 1.5 Co 0.5 @N-CNT/NFs. And the preparation of RuNi nanoparticles embedded in NCNFs (Ru 1 Ni 1 -NCNFs) was also demonstrated by Lu's group [121] as outstanding OER electrocatalysts, which shows superior low overpotential of 290 mV at 10 mA cm −2 . The origin of outstanding reactivity is closely linked to modified electronic structure and high surface roughness of Ru 1 Ni 1 -NCNFs.…”

Electronic modulation and interface engineering of electrospun nanomaterials‐based electrocatalysts toward water splitting

“…By using such electrocatalysts as both cathode and anode, low‐cost water splitting electrolyzer can be realized, which avoids the usage of different equipment and processes for the different types of HER and OER electrocatalysts. Similarly, to enhance the overall water splitting performance, the electronic modulation and interface engineering of the electrocatalysts are also desirable 199‐213 …”

“…As discussed above, bimetal nanomaterials are both HER and OER electrocatalysts, which can be constructed to be an electrolyzer for overall water splitting. Our group has developed an electrospinning and carbonization strategy to prepare bimetal RuNi nanoparticles encapsulated in N‐doped CNFs (RuNi‐NCNFs) as bifunctional electrocatalysts for overall water splitting application 206 . The introduction of Ni down‐shifts the d ‐band center of the RuNi hybrid and boost the water dissociation to H*, while Ru promotes the H 2 formation.…”