Methods of making catalysts for oxidation of unsaturated and/or saturated aldehyde to unsaturated acids is disclosed where the catalyst including at least molybdenum (Mo) and phosphorus (P), where the catalyst has a pore size distribution including at least 50% medium pores and if bismuth is present, a nitric acid to molybdenum mole ratio of at least 0.5:1 or at least 6.0:1 moles of HNO3 per mole of Mo12.