The　surface　plasmon　resonance　(SPR)　of　plasmonic　metals　is　an　effective　strategy　for　enhancing　photocatalytic　efficiency.　Herein,　we　successfully　synthesized　the　SPR-promoted　Bi/Bi2WO6　heterojunction　photocatalysts　by　in　situ　reduction　of　Bi3　+　in　Bi2WO6　nanosheets　to　plasmonic　Bi　via　a　facile　solvothermal　method.　The　size　of　Bi　nanoparticles　on　the　surface　of　Bi2WO6　was　adjusted　by　varying　the　solvothermal　temperature.　After　15　min　of　visible　light　irradiation,　the　Bi/Bi2WO6　heterojunction　with　a　suitable　size　of　metal　Bi　obtained　after　solvothermal　treatment　at　160°C　exhibited　100　%　degradation　of　Rhodamine　B　(RhB),　which　was　2.3　times　greater　than　that　of　the　pure　Bi2WO6.　The　excellent　photodegradation　performance　of　this　sample　can　be　attributed　to　the　SPR　effect　of　metal　Bi,　which　enhances　light　absorption,　generates　active　sites　and　species,　and　facilitates　rapid　carrier　transfer.　Additionally,　the　formation　of　the　Bi/Bi2WO6　Schottky　heterojunction　promotes　carrier　separation　and　minimizes　the　recombination　of　photogenerated　electron-hole　pairs.　Furthermore,　a　potential　mechanism　for　the　photodegradation　process　of　the　synthesized　photocatalyst　has　been　proposed.　This　work　not　only　offers　new　perspectives　on　in　situ　fine-tuning　strategies　for　Bi-based　photocatalysts　but　also　demonstrates　the　potential　of　low-cost　metallic　Bi　as　a　viable　alternative　to　noble　metals　for　enhancing　photocatalytic　performance.　©　2025　Elsevier　B.V.