The three types of catalyst are positive, negative and auto-catalytic. <span>A positive catalyst increases the activation energy which decreases the rate or speed of the reaction. A negative catalyst decreases the activation energy which increases the rate or speed of thee reaction. An auto-catalyst starts slows and the reaction continues itself based on the products formed.</span>
They are more likely to be covalent as covalent compounds usually tend to be radical on the color spectrum with deep purples and blacks and even earwax colored.
