Development of efficient and cost-effective transition metalbased catalysts for overall water splitting is desired. Herein, a facile synthesis procedure for the development of FeCo bimetallic alloy nanoparticles (NPs) located on the tips of multiwalled carbon nanotubes (CNTs) supported over N-doped carbon nanofibers (CNFs) is presented. The CNTs, not only prevent FeCo NPs from agglomeration by encapsulating them at the tip but also provide an efficient electron pathway. The materials exhibited excellent performance in oxygen evolution reaction (OER) and decent activity in hydrogen evolution reaction (HER) with long-term durability of up to 48 hours on glassy carbon electrode. The best OER activity with a overpotential of 283 mV@10 mAcm À 2 and Tafel slope of 38 mV/dec was achieved with a hierarchically porous catalyst having Fe : Co molar ratio of 1 : 2. This synthesis approach is promising for growing well-dispersed CNTs over N-doped carbonaceous support using bimetallic alloys for electrocatalytic applications.catalyst's intrinsic resistance and facilitating the charge transfer between catalyst and the electrolyte interface. This work might introduce a new and cost effective way for the homogenously distributed in-situ growth of CNTs over N doped carbonaceous support that have potential applications as electrocatalyst in metal air batteries, water splitting and fuel cells.

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We report the synthesis of titania nanofibers (TNF) of ∼ 195 nm mean diameter doped with phosphorus through one-pot electrospinning followed by decoration of Ag nanoparticles (NPs). The Ag NPs of ∼ 8 nm size on 2 % P-doped TNFs (Ag-PTNFs) showed excellent photocatalytic activity for the reduction of Cr(VI), under simulated solar light, with ∼ 100 % conversion to Cr(III) in 90 min at pH 3 with a pseudo-first order rate constant of 0.085 min À 1 that is 96.5 % higher than TNFs. The Ag-PTNFs also exhibited excellent photodegradation of methylene blue with pseudo-first order rate constant of 0.052 min À 1 which is 82.7 % better than TNFs. The enhanced photocatalytic performance of Ag-PTNFs is attributed to the reduced band-gap, increased charge separation and reduced recombination rates. A proposed photocatalytic mechanism based on the synergistic effect of both Ag and P doping is presented which highlights the potential of these composite materials for water remediation.

Nickel-based chalcogenides have recently gained considerable interest due to their potential as efficient electrocatalysts for overall water splitting. For example, nickel sulfide (NiS x ) with suitable chemisorption energy for both oxygen- and hydrogen-containing intermediates can catalyze both half-cell reactions. Here, we report the synthesis of Ni3S2 nanostructures of ∼8 nm mean size, anchored over electrospun N-doped carbon nanofibers using microwave synthesis. Careful optimization of the process parameters enabled the structural synthesis of three different types of Ni3S2 (mostly amorphous, partially crystalline, and mostly crystalline) over carbon nanofibers. Scanning and high-resolution transmission electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the catalysts and electrochemical performance evaluated in an alkaline medium. The partially crystalline phase of Ni3S2 supported over carbon nanofibers was the best-performing catalyst for the oxygen evolution reaction (OER) due to its high electrochemically active surface area, N-doping of carbon, presence of a crystalline and amorphous mixed phase, and high conductivity of the carbon support which resulted in a low overpotential of 270 mV for the OER with a Tafel slope of only 51 mV/dec and a low charge transfer resistance of 1.08 Ω. Moreover, the catalyst was stable and yielded more than 95% Faradaic efficiency in both the oxygen evolution and hydrogen evolution reactions.

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