The tip effect of the high curvature tip top can cause electromagnetic effects to improve the catalytic performance. Doping of transition metals (Cr, Fe and Mo) into CoP array nanocones alters the tip curvature of CoP to strengthen the tip effect with increasing curvature. The stronger tip effect of Fe-CoP improves OH⁻ concentration, accelerates surface charge transfer and enhances the electric field for a higher catalytic efficiency. Fast charge transfer and high electronic conductivity are attributed to transition metal doping, which can be confirmed by theoretical simulations and experiments. The optimized d-band centre of Fe-CoP adjusts the appropriate adsorption strength of the reaction intermediates. Fe doping endows CoP with a higher curvature cone structure and optimizes electronic structure for high catalytic activity and reaction kinetics. Tip cone as special sites tuned by transition metal doping provides a strategy for efficient non-noble metal catalysis.

Metal–support interaction (MSI) is considered a key effect of electronic and geometric structures of catalysts on tuning catalytic performance. The oxygen evolution reaction (OER) is a crucial process during energy conversion and storage. However, the OER process requires the help of noble metal catalysts to reduce the reaction overpotential, enhance reactivity with intermediates, and maintain good operating stability. Carbon–supported metal catalysts have been considered candidates for noble metal catalysts for OER. MSI occurs at the interface of carbon supports and metals, affecting the catalytic performance through electronic and geometric modulation. MSI can influence the catalytic performance and change reaction pathways from charge redistribution, electron transfer, chemical coordination and bonding, and steric effect. Connecting MSI effects with the OER mechanism can provide theoretical guidance and a practical approach to the design of efficient catalysts, including the modulation of particle size, morphology, heteroatom doping, defect engineering, and coordination atom and number. Advantage can be taken of MSI modulation between metal compounds and carbon supports to provide guidance for catalyst design.

In the past decades, the families of negative thermal expansion (NTE) materials have been in the uninterrupted growth with more new NTE materials reported; in particular, metal fluorides as the new members begin to draw attention. Herein, recent progress on the NTE properties of metal fluorides is reviewed, including compounds, mechanisms and the control of thermal expansion. Although some achievements have been made, there are still great development prospects. More in-depth investigations on metal fluorides with NTE behavior are expected

Cr, P co-doped Co₃S₄ realized the regulation of bulk and surface electronic structures for enhanced catalytic activity in the oxygen evolution reaction.