The catalytic hydrogenation of CO₂ or bicarbonates to give formic acid derivatives provides the basis for a renewable chemical feedstock. It has the potential to replace the use of the more toxic CO, which is currently utilized in industry on a million-ton scale. Noble-metal complexes have mainly been studied as catalysts for this transformation with good results. Cheaper, non-precious-metal catalysts have scarcely been investigated and the obtained catalytic activities are low with turnover numbers (TONs) <120.

Matthias Beller and co-workers, Rostock University, Germany, report cobalt dihydrogen complexes based on the tetraphos ligand (P(CH₂CH₂PPh₂)₃) for the catalytic hydrogenation of CO₂ and bicarbonates. Hydrogenation of CO₂ in methanol proceeded smoothly in 83 % yield with a TON of 659. The hydrogenation of CO₂ was also possible at low pressures with TONs of around 60. Previously reported TONs at low H₂ pressure are in the range of 9–16. For the hydrogenation of bicarbonates, a TON of 3877 was achieved. This is six times as high as the best non-precious-metal catalyst, and twice that of the best precious-metal system.

This represents a good starting point for further improvement of the hydrogenation reaction under ambient conditions and with low-cost metals.

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• Catalytic Hydrogenation of Carbon Dioxide and Bicarbonates with a Well-Defined Cobalt Dihydrogen Complex
  C. Federsel, C. Ziebart, R. Jackstell, W. Baumann, M. Beller,
  Chem. Eur. J. 2011.
  DOI: 10.1002/chem.201101343