Enhanced Hydrogen Release from Hydrogen Boride Nanosheets via Carbon Doping

Hydrogen boride (HB) nanosheets, which exhibit unique BHB bonding and intrinsic hydrogen release properties, show improved performance upon carbon doping. Herein, the synthesis of carbon‐doped HB via ion exchange is demonstrated by using carbon‐doped MgB 2 as a precursor. Comprehensive spectroscopic analyses inferred carbon substitution at boron sites, leading to structural distortions and electronic modifications. These changes weaken BHB bonds, thereby facilitating improved hydrogen release under both thermal and ultraviolet (UV) stimuli. Temperature‐programed desorption measurements reveal a reduction in the activation energy for intralayer hydrogen desorption with increasing carbon content, while UV‐induced hydrogen evolution shows a markedly lower onset threshold. Density functional theory calculations support these experimental findings, further demonstrating elongation of BB distances and shifts in vibrational modes. Overall, these results establish carbon doping as an effective strategy for modulating the chemical and electronic environment of HB, offering a promising pathway toward high‐efficiency, tunable hydrogen storage, and release materials.