Silicon-Based Sodium Hydride Core–Shell Structure for Portable Hydrolytic Hydrogen Generation

Abstract

Hydrogen production from silicon (Si) hydrolysis is environmentally friendly, safe, portable, and promising. However, the self-protected oxide layer around Si and a sluggish hydrolysis rate impede its practical utilization. To address this problem, we introduced sodium hydride (NaH) to form the core–shell structure of NaH/Si composites via a straightforward one-step, hand-mixing method in an ambient environment. NaH-based Si-M composites exhibit 83% hydrogen yield and a 52.7 mL/min hydrogen generation rate at 1–0.7 molar ratios. The hydrolytic activity includes the breakdown of NaH and the continuous hydrolysis of Si. X-ray diffraction, scanning electron microscopy, nanoindentation, and reaction observation studies have verified that NaH is pivotal in promoting thorough Si hydrolysis and attaining the maximum achievable yield compared to calcium hydride (CaH₂). NaH/Si composites showed excellent hydrogen generation performance compared to CaH₂/Si composites with microstructure silicon Si-S ≈ 1–3 μm, Si-M ≈ 75 μm, and Si-L ≈ 75–425 μm. Our study provided an innovative design and idea for utilizing cost-effective and easily transportable hydrogen production materials for practical applications, which has the potential for further advancement.