Noble metal-free catalysts

Saalfrank JW, Maier WF. 2004. Directed evolution of noble-metal-free catalysts for the oxidation of CO at room temperature. Angew Chem Int Ed 43 2028-2031. 

Secondly, the topic addressed the quest for active and cost-effective noble-metal-free catalysts for DRM, an important reaction for mitigation of greenhouse effects and production of syngas. Manganese oxides as promoters for DRM catalysts showed superior promotional effects compared to other basic oxides and partially reducible oxides. Their role relied on the suppression of metal-catalyst deactivation and coke deposition. The use of manganese oxides as promotors for DRM is still growing, but the already obtained results anticipate great potential in their application. 

The successful application of noble metal-free catalysts in the light-driven hydrogen evolution with ruthenium photosensitizers [88,89] has triggered the... 

IR-thermography and combinatorial library design (doping and composition spread) lead in a few generations to new, noble-metal-free catalysts for the low-temperature oxidation of CO in air. Activity patterns could be derived from the emissivity-corrected IR thermographic image of a catalyst library. 

Vijay, R., Hendershot, R.J., Rivera-Jimenez, S.M. et al. (2005) Noble metal free NO storage catalysts using cobalt discovered via high-throughput experimentation. Catal. Commun., 6, 167. 

The interest in noble metal free chalcogenides has recently been renewed. The Campbell group reported in 2006 on the use of Co-Se catalysts for ORR.197 The group also indicated they were involved in a more extensive study of non-precious metal chalcogenides as ORR catalysts. 

Zouc, X. Zhang, Y. Noble metal-free hydrogen evolution catalysts for water splitting. Chem. Soc. Rev., 2015, 44, 5148-5180. 

Cui H-H, Wang J-Y, Hu M-Q, Ma C-B, Wen H-M, Song X-W, Chen C-N (2013) Efficient photo-driven hydrogen evolution by binuclear nickel catalysts of different coordination in noble-metal-free systems. Dalton Trans 42(24) 8684—8691. doi 10.1039/c3dt50140j... 

At this point we note that the bio-inspired approach, coupled with nanochemical tools, allowed the preparation of the first noble metal-free catalytic materials for H" /H2 evolution working in both directions and without overpotential requirement. However, the current densities displayed by these materials are in the 1-lOmA/cm range, depending on temperature, while that of Pt-based active layers currentiy developed for electrolyzers and fuel cells exceed 1 A/cm. There is thus still room for improvement Both the optimization of the turnover frequency of the molecular catalysts and the increase of the catalyst loading within the tridimensional architecture of the electrode will allow improving the performances of such bio-inspired materials. 

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