Catalytic reduction of nitrophenol is an important reaction for both the removal of nitrophenol-containing pollutants and the achievement of aminophenol chemicals. Bimetallic AuPd nanoparticles are studied as catalysts in the reduction of 4-nitrophenol. Colloidal and inorganic material–supported AuPd catalysts are synthesized, and their catalytic activities are evaluated. The formation and structure of the catalysts are characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectronic spectroscopy. Layered materials including Mg(OH)2/MgO and graphene serve as supporters. Their remarkable promotion effects are confirmed on catalytic activities of AuPd nanoparticles. The apparent reaction rate constants are enhanced with low activation energies over the supported AuPd catalysts. Transformation of MgO to Mg(OH)2/MgO occurs during the supporting process of AuPd nanoparticles, resulting in the enhanced catalytic activity. Graphene with poly(vinylpyrrolidone) helps the formation of uniform and small-sized AuPd nanoparticles. The graphene-supported AuPd shows the most superior catalytic activity. The apparent rate constant is 10.5 min−1 in the reduction of 4-nitrophenol. The present layered materials would be suitable supporters for improving catalytic activities of other metal nanoparticles.