Abstract

With mounting concerns over critical element sustainability in future bio-refineries, the conversion of phyto-extracted nickel (from contaminated lands) into an inexpensive and clean catalyst could help to reduce demand for virgin precious metals. Utilizing this green approach, noble metal catalysts, which require substantial downstream processing, could potentially be replaced by a naturally developed non-noble metal catalyst. We report a biologically bound non-noble metal catalyst (Ni-phytocat, 0.1–2.5 wt% Ni) prepared using simple, one-step, energy efficient, microwave-assisted pyrolysis (250℃, 200 W, <10 min). The biologically bound Ni in the plant matrix directs the catalytic hydrogenation of cinnamaldehyde selectively and efficiently (up to 97% conversion and 96% selectivity at T≤120 ℃), Our findings indicate that the presence of bio-carbon matrix around the phyto-extracted Ni enables an efficient suppression of the over-hydrogenation reaction pathway and prevents further dissociation of adsorbed hydrocinnamaldehyde molecules. The simplicity, long-term stability and ease of handling make this catalyst an economically and environmentally attractive alternative to Raney nickel and precious metal–based catalysts.