It is interesting to study which combination of properties is a potential bottleneck in designing an optimal photocatalytic material. We must inspect the off-diagonal entries in Figure to see this. . By definition, the number of orange dots is the same as in (m * red , Λ). The total number of materials that meet the m * red criterion is less than those that meet the Λ criterion; we have fewer purple dots, but also, here, they cover most of the design space. These observations show that there is little correlation between these two criteria.