Interfacial Strain-Modulated Nanospherical Ni2 P by Heteronuclei-Mediated Growth on Ti3 C2 Tx MXene for Efficient Hydrogen Evolution

In situ growth engineering of ultrathin dendritic PdNi nanosheets on nitrogen-doped V2CTx MXenes for efficient hydrogen evolution

Immobilizing metal nanoparticles on a support is crucial for catalysts' stability and spatial distribution. MXenes are promising substrates for in situ growth engineering of various electrocatalysts owing to their merits. A stronger binding capacity can be achieved between the in situ-fabricated catalysts and MXenes compared to a common physical combination. Thus, synergistically utilizing morphology modulation, composition optimization, and the interfacial interaction between metal catalysts and supports will maximize the electrocatalytic activity. However, most reported in situ-formed catalysts on MXenes result in solid 0D nanoparticles and in situ growth of nanoalloy catalysts on MXenes with a precisely controlled morphology is still lacking. Herein, nanodendritic PdNi alloys are in situ grown on nitrogen-doped V2CTx, serving as efficient electrocatalysts toward the hydrogen evolution reaction (HER). Thanks to the synergistic effect of the unique nanodendritic structure of PdNi, the merits of N-TBA-V2CTx nanosheets, and the strong metal-support interaction between the PdNi and the N-TBA-V2CTx support, the in situ-formed Pd58Ni42/N-TBA-V2CTx electrocatalyst shows excellent HER performance with an ultralow overpotential of 44.1 mV to achieve 10 mA cm-2 and a lowest Tafel slope of 39.4 mV dec-1, which outperforms Pd58Ni42/TBA-V2CTx, Pd58Ni42, and Pd/C. Remarkably, the Pd58Ni42/N-TBA-V2CTx catalyst can maintain 92.3% of its initial activity even after 50 h of continuous operation.

Interface regulation of Zr-MOF/Ni2P@nickel foam as high-efficient electrocatalyst for pH-universal hydrogen evolution reaction

Currently, the development of economical and effective non-noble metal electrocatalysts is vital for advancing hydrogen evolution reaction (HER) and enabling its widespread applications. The customizable pore structure and enormous surface area of metal-organic frameworks (MOFs) have made them to become promising non-noble metal electrocatalysts for HER. However, MOFs have some challenges, including low conductivity and instability, which can result in them having high overpotentials and slow reaction kinetics in electrocatalytic processes. In this work, we present an innovative approach for synthesizing cost-effective and high-efficient Zr-MOF-derived pH-universal electrocatalysts for HER. It entails creating the interfaces of the electrocatalysts with suitable proportions of phosphide nanostructures. Zr-MOF/Ni2P@nickel foam (NF) electrodes with interface regulated by Ni2P nanostructures were successfully developed for high-efficient pH-universal HER electrocatalysts. The presence of Ni2P nanostructures with abundant active sites at the Zr-MOFs@NF interfaces boosted the electronic conductivity and local charge density of the hybrid electrocatalysts. This helped to improve their reaction kinetics and electrocatalytic activity. By optimizing the Ni2P amount, Zr-MOF/Ni2P@NF demonstrated impressive stability and superior HER activities, with a low overpotential of 149 mV (acidic electrolytes) and 143 mV (alkaline electrolytes) at 10 mA cm-2. The proven strategy in this work can be expanded to many types of MOF-based materials for wider practical applications.

Lattice Strain Engineering of Ti3C2 Narrows Band Gap for Realizing Extraordinary Sonocatalytic Bacterial Killing

The rapid development of sonodynamic therapy (SDT) provides a promising strategy for treating deep-seated multidrug-resistant (MDR) bacterial infection. However, the extreme scarcity of biologically functional and highly efficient sonosensitizers severely limits the further clinical practice of SDT. Herein, the lattice-strain-rich Ti3C2 (LS-Ti3C2) with greatly improved sonosensitizing effect is one-step synthesized using Ti3C2 and meso-tetra(4-carboxyphenyl)porphine (TCPP) by the solvothermal method for realizing extraordinary SDT. The intervention of TCPP causes all the Ti-O chemical bonds and most of the Ti-F chemical bonds on the surface layer of Ti3C2 to break down. The amino groups of TCPP are then recombined with these exposed Ti atoms to perturb the order of the Ti atoms, resulting in displacement of the Ti atoms and final lattice structural distortion of Ti3C2. The inherent lattice strain narrows the band gap of Ti3C2, which mainly facilitates the electron-hole pair separation and electron transfer under ultrasound irradiation, thereby resulting in US-mediated reactive oxygen species (ROS) production and the subsequent robust bactericidal capability (99.77 ± 0.16%) against methicillin-resistant Staphylococcus aureus (MRSA). Overall, this research offers a perspective into the development of Ti-familial sonosensitizers toward SDT practice.

Defect engineering and atomic doping of porous Co-Ni2P nanosheet arrays for boosting electrocatalytic oxygen evolution

Electrochemical hydrogen production by splitting water is mainly limited to the oxygen evolution reaction (OER), which requires high energy consumption. The design of an efficient and stable electrochemical catalyst is the key to solving this problem. Here, a three-dimensional porous Co-doped Ni₂P nanosheet (Co-Ni₂P/NF-corr) was synthesized by simple hydrothermal, acid leaching and phosphating processes successively. Excitingly, the current density of Co-Ni₂P-corr in 1 M KOH solution can reach 50 mA cm^-2 with only 267 mV overpotential. Moreover, the Tafel slope is very small, only 64 mV dec^-1. In addition, the stability test shows that it can work stably at 50 mA cm^-2 current density for at least 48 h.