The　energy　recovery　mechanism　in　water　treatment　is　investigated　through　photocatalytic　synergistic　heavy　metal　reduction　and　H2O2　production.　Herein,　two-dimensional　nickel　phthalocyanine　(NiPc)　is　anchored　on　anatase　TiO2　through　a　facile　reflux　process.　The　robust　NiPc/TS　interface　facilitates　photoelectron　cascade　transfer　and　photoreduction　of　Cr(VI)　and　O2　by　manipulating　the　3d　orbitals　of　Ni　centers　via　the　electron-　donating　effect,　resulting　in　a　remarkable　H2O2　production　rate　of　1744　mu　mol　L-　1　h-　1　for　NiPc/TS-0.35　in　the　presence　of　Cr(VI).　We　reveal　that　the　reduced　population　of　bonding　orbital　electrons　in　the　Ni　center　and　Cr(III)　hybrid　orbital　accelerates　product　desorption,　thereby　enhancing　the　regeneration　of　active　catalytic　sites　and　enabling　O2　activation　and　H2O2　transformation.　This　study　demonstrates　a　scheme　for　recovering　chemical　energy　to　produce　hydrogen　peroxide　through　the　photoreduction　of　Cr(VI),　providing　a　promising　strategy　for　resource　recovery　from　wastewater.