Electrode catalyst layer for fuel cell, and solid polymer-type fuel cell comprising said electrode catalyst layer

1. An electrode catalyst layer for a fuel cell, comprising a catalyst/support composite comprising a support and a catalyst supported on the support,

wherein the support contains a titanium oxide,

a surface of the catalyst/support composite has an oxide of at least one element selected from the group consisting of niobium, tantalum, zirconium, and silicon, and

a ratio A2/A1 is from 0.35 to 1.70, wherein A1 is an atomic ratio of titanium on a surface of the catalyst layer and A2 is an atomic ratio of a total of niobium, tantalum, zirconium, and silicon on the surface of the catalyst layer, A1 and A2 being measured by X-ray photoelectron spectroscopy.

2. The electrode catalyst layer according to claim 1 , wherein the titanium oxide has a composition TiO x (0.5≤x<2).

3. The electrode catalyst layer according to claim 1 , wherein the catalyst contains platinum, or an alloy of platinum and one or more of iridium and ruthenium.

4. The electrode catalyst layer according to claim 1 , further comprising an ionomer,

wherein a ratio I/M is from 0.06 to 0.25, wherein I is a mass of the ionomer and M is a mass of the catalyst/support composite.

5. A solid polymer fuel cell comprising the electrode catalyst layer according to claim 1 as an anode catalyst layer.