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The development of cost‐effective electrocatalysts with high activity and sufficient stability for hydrogen evolution reaction (HER) is crucial for the widespread application of water electrolysis for sustainable H2 production. Transition metal oxides are desirable alternatives to replace benchmark Pt‐based HER electrocatalysts because of their cost effectiveness, facile synthesis, versatile compositions, and easy electronic structure tuning. However, most available transition metal oxides show poor performance for HER catalysis. Here, it is reported that the anatase TiO2 can be efficiently developed into a superior HER electrocatalyst with comparable activity to Pt‐based electrocatalysts in alkaline solution through simultaneous morphology control, proper lattice doping, and surface active sites engineering. Specifically, the obtained cobalt‐doped TiO2 nanorod arrays (Co‐TiO2@Ti(H2)) show a low overpotential of only 78 mV at 10 mA cm−2, a small Tafel plot of 67.8 mV dec−1, and excellent stability even at an ultralarge current density of ≈480 mA cm−2 in 1.0 m KOH solution. Theoretical calculations demonstrate that the introduction of Co with rich oxygen vacancies can efficiently lower the energy barrier for water adsorption/dissociation and H intermediate desorption. This work uncovers the potential of the low‐cost transition metal oxides as alternative HER electrocatalysts in alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiO x ) is one of the most promising hole transport materials for inverted perovskite solar cells (PSCs). However, its application is severely restrained due to unfavorable interfacial reactions and insufficient charge carrier extraction. Herein, a multifunctional modification at the NiO x /perovskite interface is developed via introducing fluorinated ammonium salt ligand to synthetically solve the obstacles. Specifically, the interface modification can chemically convert detrimental Ni ≥3+ to lower oxidation state, resulting in the elimination of interfacial redox reactions. Meanwhile, interfacial dipole is incorporated simultaneously to tune the work function of NiO x and optimize energy level alignment, which effectively promotes the charge carrier extraction. Therefore, the modified NiO x -based inverted PSCs achieve a remarkable power conversion efficiency (PCE) of 22.93%. Moreover, the unencapsulated devices obtain a significantly enhanced long-term stability, maintaining over 85% and 80% of the initial PCEs after storage in ambient air with a high relative humidity of 50-60% for 1000 h and continuous operation at maximum power point under one-sun illumination for 700 h, respectively., (© 2023 Wiley-VCH GmbH.)

A H 2 SO 4 -Ti 3 C 2 T x ion-gel is in situ fabricated to prevent the restacking of Ti 3 C 2 T x for high-rate micro-supercapacitors. The ion-gel pillared by an electrolyte possesses an enlarged interlayer spacing facilitating ion transport. Furthermore, a bilayer structure is designed with dry Ti 3 C 2 T x for fast electron conduction. The bilayer Ti 3 C 2 T x film shows improved capacitance from 49% to 73% of the initial capacitance at a high scan rate of 200 mV s -1 , along with excellent cycle stability. This study opens up a concise and efficient way for high-performance micro-supercapacitors.

The development of cost-effective electrocatalysts with high activity and sufficient stability for hydrogen evolution reaction (HER) is crucial for the widespread application of water electrolysis for sustainable H 2 production. Transition metal oxides are desirable alternatives to replace benchmark Pt-based HER electrocatalysts because of their cost effectiveness, facile synthesis, versatile compositions, and easy electronic structure tuning. However, most available transition metal oxides show poor performance for HER catalysis. Here, it is reported that the anatase TiO 2 can be efficiently developed into a superior HER electrocatalyst with comparable activity to Pt-based electrocatalysts in alkaline solution through simultaneous morphology control, proper lattice doping, and surface active sites engineering. Specifically, the obtained cobalt-doped TiO 2 nanorod arrays (Co-TiO 2 @Ti(H 2 )) show a low overpotential of only 78 mV at 10 mA cm -2 , a small Tafel plot of 67.8 mV dec -1 , and excellent stability even at an ultralarge current density of ≈480 mA cm -2 in 1.0 m KOH solution. Theoretical calculations demonstrate that the introduction of Co with rich oxygen vacancies can efficiently lower the energy barrier for water adsorption/dissociation and H intermediate desorption. This work uncovers the potential of the low-cost transition metal oxides as alternative HER electrocatalysts in alkaline water electrolysis., (© 2021 Wiley-VCH GmbH.)