A novel strategy for the fabrication of highly active and stable hydrochar-based catalysts for efficient dry reforming of methane

Abstract

Strong metal-support interaction (SMSI) has pivotal importance for stabilizing metal sites and tuning catalytic performance in high-temperature gas phase chemistry. Conventional SMSI construction strategy, however, suffers from limited exposure of active sites caused by gas or thermally-induced metal redistribution and heavily deteriorates the catalytic performance. Herein we showed that the rationally constructed metal–carbon interface by pressure-induced SMSI greatly impacted the activity of core–shell nickel nanoparticles supported on hydrochar (Ni/NiO/HC) in dry reforming of methane (DRM). The electronic and geometric structures of Ni/NiO/HC were effectively tailored by simply adjusting the compression pressure. In particular, the NiO shell thickness was highly sensitive to compression pressure, which could be precisely manipulated from 2 to 5 atomic layers by imposing the pressures from ambient to 3.6 Gpa. With the optimized thickness of NiO shell of 3–5 atomic layers, the highest activity of Ni/NiO/HC catalysts were up to 57.2 times than their uncompressed analogues in DRM, and far outperformed benchmarks in the literature, especially at low reforming temperatures (500–600 °C). The active sites responsible for this promising performance were associated with the fraction of low-coordinated corner and perimeter Ni atoms from 20.1 to 61.6%, which dramatically enhanced the DRM activity of Ni/NiO/HC catalysts over 2 orders of magnitude. This study introduced a new paradigm for SMSI construction via a pressure-induced construction strategy and highlighted the importance of a rationally designed core–shell metal particles/hydrochar interface.