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Flexible Bifunctional Electrode for Alkaline Water Splitting with Long-Term Stability.

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McGlynn, Ruairi J 
Boies, Adam 


Progress in electrochemical water-splitting devices as future renewable and clean energy systems requires the development of electrodes composed of efficient and earth-abundant bifunctional electrocatalysts. This study reveals a novel flexible and bifunctional electrode (NiO@CNTR) by hybridizing macroscopically assembled carbon nanotube ribbons (CNTRs) and atmospheric plasma-synthesized NiO quantum dots (QDs) with varied loadings to demonstrate bifunctional electrocatalytic activity for stable and efficient overall water-splitting (OWS) applications. Comparative studies on the effect of different electrolytes, e.g., acid and alkaline, reveal a strong preference for alkaline electrolytes for the developed NiO@CNTR electrode, suggesting its bifunctionality for both HER and OER activities. Our proposed NiO@CNTR electrode demonstrates significantly enhanced overall catalytic performance in a two-electrode alkaline electrolyzer cell configuration by assembling the same electrode materials as both the anode and the cathode, with a remarkable long-standing stability retaining ∼100% of the initial current after a 100 h long OWS run, which is attributed to the "synergistic coupling" between NiO QD catalysts and the CNTR matrix. Interestingly, the developed electrode exhibits a cell potential (E10) of only 1.81 V with significantly low NiO QD loading (83 μg/cm2) compared to other catalyst loading values reported in the literature. This study demonstrates a potential class of carbon-based electrodes with single-metal-based bifunctional catalysts that opens up a cost-effective and large-scale pathway for further development of catalysts and their loading engineering suitable for alkaline-based OWS applications and green hydrogen generation.


Publication status: Published


alkaline electrolyzer cell, bifunctional and flexible electrode, hydrogen evolution reaction (HER), long-term OWS stability, macroscopically assembled carbon nanotube (CNT) ribbons, nickel oxides (NiO) quantum dots (QDs), overall water splitting (OWS) in alkaline media, oxygen evolution reaction (OER), plasma-induced nonequilibrium electrochemistry (PiNE), water electrolysis

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ACS Appl Mater Interfaces

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American Chemical Society (ACS)
Engineering and Physical Sciences Research Council (EP/M015211/1)