Layered TiO₂ Nanosheet‐Supported NiCo₂O₄ Nanoparticles as Bifunctional Electrocatalyst for Overall Water Splitting

Abstract

Exploring the generation of efficient and long‐lasting bifunctional electrocatalysts obtained from low‐cost transition metal oxides is crucial to the optimal production of hydrogen and oxygen by electrocatalytic water splitting. This study aims to demonstrate the applicability of layered TiO2 nanosheets as support for designing electrocatalysts. We have demonstrated the performance by decorating the TiO2 support with NiCo2O4 nanoparticles (NiCo2O4/TiO2) as catalysts for electrocatalytic overall water splitting. Moreover, the corrosion effect of usually used carbon‐based supporting materials can decrease the working efficiency and, thus, the overall performance of the catalysts. In this aspect, TiO2 can be a better alternative to carbon‐based systems. Layered TiO2 was synthesized at room temperature, and a simple heat treatment protocol was employed for the large‐scale synthesis of NiCo2O4/TiO2. TiO2 facilitated the formation of smaller NiCo2O4 nanoparticles, also improving the dispersion. This bifunctional electrocatalyst exhibits high OER and HER performance with a low overpotential of 309 mV and 185 mV respectively, at a current density of 10 mA cm−2. TiO2 supported catalyst also exhibits other advantages like remarkable durability in the alkaline medium along with high turnover frequency (TOF) values. This inexpensive catalyst can deliver a current density of 10 mA cm−2 at only 1.64 V with a steady performance for more than 12 h for overall water splitting. Thus, this homemade system provides a proficient and low‐cost alternative to the more expensive systems such as RuO2, IrO2 or Pt for the electrochemical water splitting applications.

Heterogeneous Synergetic Effect of Metal–Oxide Interfaces for Efficient Hydrogen Evolution in Alkaline Solutions

“…At an overpotential of 100 mV, the TOF for R-Ni 17 W 3 /WO 2 was up to 0.62 H 2 s −1 . Referring to the nonprecious catalysts previously reported in Figure 4f and Table S1, the Ni 17 W 3 /WO 2 HER performance was better than, or at least comparable to, Ni 4 Mo/GNS (0.11 at 100 mV) 42 and NiCo 2 O 4 (0.17 at 100 mV), 43 which indicated that the S12a). The Ni 17 W 3 alloy particles on Ni 17 W 3 /WO 2 were then etched away using a 0.1 M H 2 SO 4 aqueous solution, as confirmed by XRD (Figure S12b), and the processed samples were referred to as E-Ni 17 W 3 /WO 2 @CP.…”

Three‐dimensional Pt catalyst on TiO2 structures: Synthesis, characterization, and optimal morphology for efficient ethanol electro‐oxidation in acidic medium

“…TiO 2 is cheap, commercially available, nontoxic, and possesses a high mechanical and corrosion resistance. Since its discovery for electrochemical photocatalysis of water at a semiconductor electrode, [ 1–2 ] TiO 2 received a lot of interest and was extensively employed in numerous technologies such as photocatalytic degradation of pollutants, [ 3 ] water splitting, [ 4–5 ] photocathode for the photoelectrochemical hydrogen evolution from water, [ 6 ] solar cells, supercapacitors, lithium‐ion batteries, biomedical devices, [ 7 ] and implants for bone tissue engineering. [ 8 ]…”

N-doped TiO2 nanotube arrays with uniformly embedded CoxP nanoparticles for high-efficiency hydrogen evolution reaction

“…Titanium oxide nanotube arrays (TiO 2 NTAs) have been proposed as a support substrate for superior electrochemical electrodes in many eld because of the unique hollow structure, effective electron transfer pathways, and excellent physical and chemical stability under a wide variety of conditions. [26][27][28][29][30][31][32] More important, the highly ordered TiO 2 NTAs prepared by anodization of Ti substrate exhibits large surface areas, and they do not require additional binders to adhere to Ti substrates. Recently, there are many literatures on the incorporation of noble metal or economic electrocatalysts on TiO 2 NTAs to decrease their overpotential for water splitting, such as RuO 2 doped TiO 2 NT for OER application, amorphous MoS xcoated TiO 2 NTAs and Ru 0.33 Se nanoparticles decorated TiO 2 NTAs for enhanced HER activity.…”