The activity and accessibility of MoS 2 edge sites are critical to deliver high hydrogen evolution reaction (HER) efficiency. Here, a porous carbon network confining ultrasmall N-doped MoS 2 nanocrystals (N-MoS 2 /CN) is fabricated by a selftemplating strategy, which realizes synergistically structural and electronic modulations of MoS 2 edges. Experiments and density functional theory calculations demonstrate that the N dopants could activate MoS 2 edges for HER, while the porous carbon network could deliver high accessibility of the active sites from N-MoS 2 nanocrystals. Consequently, N-MoS 2 /CN possesses superior HER activity with an overpotential of 114 mV at 10 mA cm −2 and excellent stability over 10 h, delivering one of best MoS 2based HER electrocatalysts. Moreover, this study opens a new venue for optimizing materials with enhanced accessible catalytic sites for energy-related applications.

Developing efficient and stable non‐noble electrocatalysts for the oxygen evolution reaction (OER) remains challenging for practical applications. While nickel–iron layered double hydroxides (NiFe‐LDH) are emerging as prominent candidates with promising OER activity, their catalytic performance is still restricted by the limited active sites, poor conductivity and durability. Herein, hierarchical nickel–iron–cobalt LDH nanosheets/carbon fibers (NiFeCo‐LDH/CF) are synthesized through solvent‐thermal treatment of ZIF‐67/CF. Extended X‐ray adsorption fine structure analyses reveal that the Co substitution can stabilize the Fe local coordination environment and facilitate the π‐symmetry bonding orbital in NiFeCo‐LDH/CF, thus modifying the electronic structures. Coupling with the structural advantages, including the largely exposed active surface sites and facilitated charge transfer pathway ensured by CF, the resultant NiFeCo‐LDH/CF exhibits excellent OER activity with an overpotential of 249 mV at 10 mA cm−1 as well as robust stability over 20 h.

Developing high-performance electrocatalysts for hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production, yet still challenging. Here, we report boron-modulated osmium (B-Os) aerogels with rich defects and ultra-fine diameter as a pH-universal HER electrocatalyst. The catalyst shows the small overpotentials of 12, 19, and 33 mV at a current density of 10 mA cm−2 in acidic, alkaline, and neutral electrolytes, respectively, as well as excellent stability, surpassing commercial Pt/C. Operando X-ray absorption spectroscopy shows that interventional interstitial B atoms can optimize the electron structure of B-Os aerogels and stabilize Os as active sites in an electron-deficient state under realistic working conditions, and simultaneously reveals the HER catalytic mechanisms of B-Os aerogels in pH-universal electrolytes. The density functional theory calculations also indicate introducing B atoms can tailor the electronic structure of Os, resulting in the reduced water dissociation energy and the improved adsorption/desorption behavior of hydrogen, which synergistically accelerate HER.

Heterojunction nanostructures usually exhibit enhanced properties in compariosn with their building blocks and are promising catalyst candidates due to their combined surface and unique interface. Here, for the first time we realized the oriented growth of ultrasmall metal nanoparticles (NPs) on metal−organic framework nanosheets (MOF NSs) by precisely regulating the reduction kinetics of metal ions with solvents. In particular, a rapid reduction of metal ions leads to the random distribution of metal NPs on the surface of MOF NSs, while a slow reduction of metal ions results in the oriented growth of NPs on the edge of MOF NSs. Impressively, the strong synergy between Pt NPs and MOF NSs significantly enhances the hydrogen evolution reaction (HER) performance, and the optimal catalyst displays HER activities superior to those of a composite with a random growth of Pt NPs and commercial Pt/C under both acidic and alkaline conditions. Moreover, the versatility of such oriented growth has been extended to other metal NPs, such as Pd, Ag, and Au. We believe this work will promote research interest in material design for many potential applications.