Hollow materials with a sophisticated structure are promising for various applications with boosted performances and innovative properties. Herein, we report an in situ transformation strategy using multi-layered MOFs as templates to fabricate multi-shelled hollow NiZnCoFe layered double hydroxides (LDHs), which outperformed the double- and single-shelled hollow LDHs and commercial IrO₂ in the oxygen evolution reaction.

Bifunctional single atomic Mn sites anchored on a B and N co-doped carbon nanotube array support (Mn-SA/BNC) were utilized as both cathodic and anodic materials in overall hydrazine splitting for high-efficiency energy-saving H₂ production.

Overall hydrazine splitting (OHzS) is a promising alternative for overall water splitting (OWS) towards hydrogen production due to the anodic hydrazine oxidation reaction (HzOR) involving less electrons and faster kinetics than the oxygen evolution reaction (OER). However, it still remains a challenge to synthesize bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and HzOR with low overpotentials. Herein, we represent a N/S co-doped hollow carbon sphere loaded with Rh nanoparticles (Rh-NS-HCS) and demonstrate its dual appealing activities for both the HER and HzOR. Notably, the obtained Rh-NS-HCS shows superiorities for hydrogen production in OHzS with a cell voltage of 0.11 V to reach a current density of 10 mA cm⁻² when it serves as both a cathodic and anodic electrocatalyst. These performances can be attributed to the intrinsic nature of the Rh nanoparticles and N/S co-doped hollow structured carbon matrix, which could provide easy access to active sites, excellent conductivity and stability, thus making energy-efficient hydrogen production possible.