A few methods, intended for CO generation in laboratory, are presented (by O. Glemser) at: Georg Brauer (Ed.); "Handbook of Preparative Inorganic Chemistry", Vol. 1, 2nd ed., Academic Press, New York and London, 1963, pp. 645-647.

The following paper may possibly be found helpful: http://link.springer.com/article/10.1007/BF02128129

About 'water gas' and 'producer gas'; which are industrial gases obtained from coal gasification that contain CO, you may check my post elsewhere at this forum: https://www.researchgate.net/post/what_is_the_difference_between_natural_gas_producer_gas_and_associated_gas

To obtain CO from CO2, you'll need to perform the reverse water gas shift reaction (RWGS) as follows:

CO2 + H2 → CO + H2O

This reacton is endothermic and the required heat of reaction is +9 kcal/mole

This RWGS reaction will require a suitable catalyst like iron and maybe others.

Hope this helps answer your question.

Professor Yehia Khalil, Yale University, USA

Fellow of the University of Oxford, UK

As Prof Khalil points out the reverse water gas shift reaction is a good way to produce CO from CO2 and H2 given a high enough residence time it will go to equilibrium at temperatures of 400 F or higher over Cu, Ni or Fe catalyst.  If you need to product CO2 ffree was you will need to scrub out the CO2(an acid)  with an amine or other appropriate (eg Carbonate) material