Processes, methods, and apparatus for carbon sequestration utilizing catalysis schemes configured to provide high concentrations of hydrated CO2 in proximity with a sequestration agent are provided. Reactants are combined with catalyst such that at least two regions of controlled catalytic activity form encompassing at least the interface between a sequestration agent and an aqueous solution containing dissolved CO2. Suitable reactants include various sequestration agents, catalyst, and carbon dioxide dissolved in an aqueous solution (seawater, for example). Possible products include bicarbonate and metal cations.