Abstract: The catalyst for electrodes comprises: a porous support which has nanopores having a pore diameter of from 1 nm to 20 nm and micropores having a pore diameter of less than 1 nm; and a plurality of catalyst particles which are supported by the support. The catalyst particles are supported by both inner portions and outer portions of mesopores of the support, and contain Pt (zerovalent). If an analysis of the particle size distribution of the catalyst particles is performed using three-dimensional reconstructed images obtained through a STEM-based electron tomography measurement, the condition of formula (S1), namely (100×(N10/N20)?8.0) is satisfied, where N10 represents the number of noble metal particles that are not in contact with pores having a pore diameter of 1 nm or more; and N20 represents the number of catalyst particles that are supported by the inner portions of the nanopores of the support.

Abstract: This catalyst for electrodes comprises: a porous carbon support which has nanopores having a pore diameter of from 1 nm to 20 nm; and a plurality of catalyst particles which are supported by the support. The catalyst particles contain Pt (zerovalent), and are supported by both inner portions and outer portions of the nanopores of the support. If an analysis of the particle size distribution of the catalyst particles is performed using three-dimensional reconstructed images obtained through a STEM-based electron tomography measurement, the proportion of the catalyst particles supported by the inner portions of the nanoparticles is 50% or more: at least one nanopore is formed in a cubic image having a side of from 20 nm to 50 nm, said cubic image being obtained from a three-dimensional reconstructed image of a catalyst aggregate; and this nanopore has the shape of a continuously extending interconnected pore.

Abstract: Provided is a catalyst for electrode that has excellent catalytic activity and that is capable of contributing toward lower PEFC costs. This catalyst for electrode includes: a hollow carbon support having nanopores with a pore diameter of 1 to 20 nm; and a plurality of catalyst particles supported on the support. The catalyst particles are supported both inside and outside the nanopores of the support, are composed of (zerovalent) Pt, and when analysis of the particle size distribution of the catalyst particles is performed using three-dimensional, reconstructed images obtained through STEM-based electron tomography measurement, the percentage of catalyst particles supported inside the nanopores is 50% or more.