A defect-derived metal-free electrocatalyst with appropriate CO2 adsorption for efficient carbon dioxide reduction.

It is a great challenge to fabricate a metal-free oxygen reduction reaction (ORR) electrocatalyst that can operate well in the acidic medium and fuel cells system. Here, a metal-free carbon material C-900 with abundant defect sites is fabricated by a self-sacrificed template and a solid-state reaction strategy. C-900 shows a superior performance to 20% Pt/C in alkaline medium and a performance closer to 20% Pt/C in acidic condition. It can thus be applied in air-breathing fuel cell (without extra operation pressure) as the cathode catalyst, which shows a high performance (1160 W L–1; ∼62% of 20% Pt/C) with excellent stability. By using oxygen temperature-programmed desorption, the strong selective chemisorption of O2 on C-900 has been revealed. The excellent chemisorption property of C-900 may originate from the large amounts of carbon defect sites, which have been confirmed by synchrotron radiation-based X-ray absorption spectroscopy. The rich defect sites and excellent chemisorption property can thus induce reversible carbon–oxygen interface for the excellent ORR activity.

In the gas–solid nanoreactor Tb(acac)3(H2O)2@ZIF-8, fluoresce of TbIII was quenched for the aldol condensation reaction of the acac ligands and HCHO gas. Thus the nanoreactor could serve as an efficient HCHO gas probe.

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