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Hydrogen peroxide production through the electrochemical two-electron oxygen reduction presents a compelling alternative to the anthraquinone process due to the cheap starting materials and low operating temperature and pressure. Transition metal species featuring with multi-active sites, offer high electrochemical activity and selectivity. MXenes, distinguished by excellent electrical conductivity and the two-dimensional structure facilitating smooth ion transportation, further enhance the prospects of this production approach. In this study, three Mo-based MXenes were synthesized: Mo 2 TiC 2 F x , Mo 2 Ti 2 C 3 F x and Mo 2 CF x. Among these, Mo 2 TiC 2 F x emerged as the most promising catalyst for 2e−ORR, achieving a remarkable H 2 O 2 yield of up to 0.54 mol·g cat −1·h−1. Moreover, it also exhibits a high H 2 O 2 selectivity ranging from 81.3 % at 0.2 V to 94.1 % at 0.6 V vs. RHE, coupled with an impressive faradaic efficiency of 76.4 % at 0.4 V using H-cell. Further analysis indicates that the superior 2e−ORR performance can be attributed to the presence of metallic Mo on the surface of Mo 2 TiC 2 F x. [ABSTRACT FROM AUTHOR]

In the paper, Pd/TiO 2 was successfully prepared by anodic oxidation and electrodeposition. When the time of depositing Pd is 15 min and 5 min, the electrocatalyst is marked as 15 min Pd/TiO 2 and 5 min Pd/TiO 2 respectively. The physical properties of Pd/TiO 2 were characterized by XRD (X-ray diffraction), EDS (energy dispersive spectroscopy), SEM (scanning electron microscope) and XPS (X-ray photoelectron spectroscopy). The catalytic activity of Pd/TiO 2 for hydrogen evolution reaction (HER) in 1 M KOH solution was characterized by the electrochemical workstation. XRD results showed that Pd/TiO 2 was successfully synthesized; the EDS and XPS results confirmed the above results. SEM results show that Pd nanoparticles are uniformly distributed on the surface of TiO 2 nanotube arrays. The electrochemical results show that Pd/TiO 2 has better catalytic activity than TiO 2. Compared with 5 min Pd/TiO 2 and TiO 2 -2h, the overpotential of 15 min Pd/TiO 2 is positively shifted by 98 mV and 588 mV, respectively. The 15 min Pd/TiO 2 still has good catalytic activity after 2000 CV cycles. The catalytic performance of all catalysts in 1 M KOH is better than that in 1 M Na 2 SO 4. Image 1 • Pd/TiO 2 was successfully synthesized by anodic oxidation and electrodeposition. • The overpotential of 15 min Pd/TiO 2 is 149 mV in 1 M KOH. • Pd/TiO 2 showed good stability in 1 M KOH for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

The key to synthesis highly efficient MoS 2 based electrocatalyst for hydrogen evolution reaction (HER) is to construct a reasonable composite system structure to improve the stability, reduce the aggregation and improve the intrinsic poor conductivity. In this paper, MoS₂ composite of erbium-based metal-organic framework (noted as Er-MOF/MoS 2) were synthesized by hydrothermal method. The morphology and structure of the synthesized samples were characterized by powder X-ray diffraction (XRD), field emission electron microscopy (FESEM), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), and the electrocatalytic performances were tested by linear sweep voltammograms (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), i-t. On the basis of the experiment, Er-MOF/MoS 2 shows improved conductivity and more exposed active sites, exhibiting excellent HER activity in acidic media, with only 234 mV overpotential to achieve 10 mA cm−2, and a Tafel slope of 54.3 mV dec−1. This strategy of porous structure of MoS 2 composite rare earth metal organic framework materials provides a novel and effective solution for preparing high performance MoS 2 based electrocatalyst. • Er-MOF and Er-MOF/MoS 2 were prepared by hydrothermal method. • Er-MOF as supports improved the catalytic activity and more exposed active sites of MoS 2 in acidic media. • Er-MOF/MoS 2 shows excellent long-term durability. [ABSTRACT FROM AUTHOR]