I have not heard of anything for sale but it might be out there. You might investigate the petrochemical refining indistry. They use alot of catalysts and I am sure they have methods to evaluate their efficiencies and other properties. No reason you could not adapt one of their tests for your work.
You might pass a solution sensitive to the catalytic action over a coated plate and measure the before and after change. The effect is probably subtle so you might recirculate the solution over the coating for some period of time. Different wavelenghts of light, temeprature, pressure, etc.