Metal-supported material and ammonia synthesis catalyst

Abstract

A metal-supported material including a transition metal excluding Group 4 elements supported on a binary composite oxide. The composite oxide includes a metal element expressed by AX, where A represents a lanthanoid that is in a partially or entirely trivalent state, X represents an element that is a Group-2 element in a periodic table selected from the group consisting of Ca, Sr, and Ba, or a lanthanoid, and that is different from A, n satisfies 0<n<1, y satisfies 0<y<1, m satisfies 0≤m<1, and n+y=1. The composite oxide includes a solid solution that is a tetragonal crystal or a cubic crystal, and a ratio of a value (D) of a dispersion degree of the transition metal obtained by an Hpulse chemical adsorption method to a value (D) of the dispersion degree predicted from an average particle diameter of particles of the transition metal obtained from a TEM image satisfies 0<D/D<1.