The design of efficient and durable photoelectrochemical water splitting devices requires that each component incorporated have optimized properties. Electrolytes with extreme pH minimize resistances, but catalyst stability at operating potentials under these conditions is not assured. The literature offers many options for catalysts, however their characteristics are typically reported under conditions selected according to the interests of the research team, and are difficult to compare to each other. JCAP has developed a protocol for heterogeneous oxygen and hydrogen evolution catalysts that enables rigorous comparisons of performance at pH 0 and pH 14, and has also evaluated several elements for standardized photoelectrochemical benchmarking. The methodology and findings will be described, and areas where advances are needed in methodology and in materials discovery will be discussed.