Tungsten　carbide　(WC)　is　commonly　used　as　a　photocatalytic　material　for　hydrogen　production　via　water　reduction.　However,　it　is　often　combined　with　an　effective　photoabsorber　to　provide　sufficient　photoactivity.　This　is　attributed　to　the　narrow　band　gap　of　WC,　which　leads　to　an　inadequate　redox　capability　for　water　reduction.　Notably,　this　limitation　was　overcome　using　a　novel　solid-liquid　photocatalytic　system　that　compliments　bare　WC　photocatalysts　with　liquid-phase　photosensitizing　erythrosine　B　(ErB).　The　proposed　concept　eliminates　the　need　to　couple　WC　with　photoabsorbing　semiconductors,　which　often　requires　tedious　procedures　for　the　proper　functionalization　of　photocatalytic　composites.　The　experimental　results　indicated　significant　hydrogen　production　from　the　proposed　solid-liquid　photocatalytic　system　under　irradiation　with　visible　light　(lambda=520　nm);　however,　only　in　the　presence　of　triethanolamine　(TEOA)　as　a　sacrificial　reagent.　Evidently,　a　blank　experiment　with　only　WC　and　ErB　under　typical　photoreaction　conditions　exhibited　nearly　zero　photoactivity　and　the　production　of　H2　was　undetected.　Similarly,　nonactivity　was　observed　for　the　photoreaction　in　the　presence　of　ErB　or　WC　in　the　irradiated　TEOA　solution.　These　blank　experiments　confirmed　the　significance　of　all　three　components,　namely　WC,　ErB,　and　TEOA,　which　functioned　as　the　photocatalyst,　photoabsorber,　and　sacrificial　reagent,　respectively,　for　suitable　H2　production　in　the　proposed　system.　The　effects　of　three　critical　parameters,　such　as　pH,　ErB　concentration,　and　WC　concentration,　were　systematically　investigated.　The　optimum　pH　for　H2　production　was　8,　with　a　slight　variation　to　more　basic　or　acidic　conditions　reducing　the　photoactivity　of　the　system.　At　pH　＜　8,　part　of　TEOA　undergoes　partial　protonation,　thereby　losing　its　activity　as　a　sacrificial　reagent　in　the　photocatalytic　system.　As　the　pH　increased　to　＞　8,　the　low　proton　concentration　in　the　reaction　medium　perturbed　the　thermodynamic　drive,　leading　to　suppressed　H2　production.　The　optimum　ErB　concentration　was　1　mmol　center　dot　L-1,　and　decreasing　or　increasing　the　ErB　concentration　from　the　optimal　point　was　detrimental　to　H2　production.　The　diluted　system　(ErB　concentration　＜　1　mmol　center　dot　L-1)　provided　insufficient　sensitizing　agents,　whereas　the　concentrated　system　(＞　1　mmol　center　dot　L-1　ErB)　induced　significant　scattering　effects　that　prevent　light　from　penetrating　into　the　reactive　liquid　phase.　Conversely,　the　WC　concentration　exhibited　a　positive　correlation　with　H2　production　in　a　steady　manner,　and　the　highest　H2　production　measured　by　the　system　was　at　a　WC　concentration　of　12　mmol　center　dot　L-1.　Under　optimum　conditions,　66　mu　mol　center　dot　h-1　of　H2　was　successfully　produced,　with　a　slightly　higher　apparent　quantum　efficiency　(AQE)　of　6.6%　at　520　nm,　which　was　attributed　to　the　synergism　of　ErB-TEOA-WC　in　the　proposed　system.　The　photoelectrochemical　evaluation　confirmed　the　positive　interactions　between　ErB,　TEOA,　and　WC,　which　caused　reduced　impedance　while　improving　charge　utilization　in　the　system.　Consequently,　an　excellent　H2　turnover　number　(TON)　of　15　was　achieved　with　negligible　activity　decay　for　at　least　20　h　of　reaction.　Density　functional　theory　(DFT)　calculations　confirmed　the　major　roles　of　W-　and　C-vacant　sites　in　H2　production,　which　were　attributed　to　their　enhanced　product　desorption　that　facilitates　high　turnover　rates　during　photoreactions.　In　conclusion,　the　proposed　novel　liquid-solid　photocatalytic　WC/ErB/TEOA　system　provides　more　facile　photo-derived　H2　energy　from　water,　which　circumvents　the　tedious　photoabsorber　coupling　of　metal　carbide　photocatalysts.