As　a　sustainable　and　economical　strategy,　electrochemical　nitrogen　reduction　reaction　(eNRR)　is　a　promising　alternative　of　energy-intensive　Haber-Bosch　process　to　produce　ammonia.　Fabricating　efficient　catalysts　for　eNRR　is　still　challenging　due　to　the　bottleneck　of　insufficient　activity　and　low　electron　selectivity.　Herein,　phosphotungstic　acid　(PTA)　as　substrate　to　anchor　cerium　species　on　the　4-fold　hollow　site　was　prepared,　which　reaches　high　ammonia　yield　rates　of　42　μg　h−1　mgcat−1　and　Faradaic　efficiencies　of　9.2　%　at　−0.6　V　versus　reversible　hydrogen　electrode.　Experiments　and　theoretical　calculations　reveal　that　the　introduction　of　Ce　species　could　significantly　improve　the　electronic　density　of　adjacent　exposed　W　atoms,　further　boosting　the　effective　adsorption　and　activation　of　N2　to　form　active　*N2.　Finally,　the　designed　Ce-PTA　catalysts　show　high　electrocatalytic　activity　of　N2　reduction　into　ammonia.　This　work　highlights　the　important　role　of　using　PTA　as　substrate　to　prepare　stable　supported　metal　species　for　heterogeneous　electrocatalysis.　©　2023