| Nowadays,with the rapid development of human society,the problem of energy shortage and environmental pollution has become a major obstacle to development.Photocatalytic technology using solar energy can not only produce hydrogen by splitting water,but also degrade organic pollutant that has becoming an effective method to solve this problem.As a kind of photocatalyst,metal sulphide has been widely used in photocatalytic hydrogen evolution of water splitting due to its suitable band structure.However,metal sulfide semiconductors have been photoetched due to their unstable chemical properties,which limits their photocatalytic stability.Also,the complex synthesis methods and high equipment requirements also limit their application.In this paper,the relatively common binary metal sulfide CdS and ternary metal sulfide ZnIn2S4 were studied,the hybrid photocatalysts CdS/CPC and CoP/ZIS with two-dimension?2D?structure were constructured successfully and their photocatalytic hydrogen production was investigated.The main contents are summarized as follows:?1?The systhesis of CdS/CPC composites and the study of their photocatalytic hydrogen production by water splittingThe collected biological waste poplar catkins were carbonized into biomass activated carbon in a tube furnace.We converted carbonized poplar catkins?CPC?microtubes into microsheets by ultrasonic crushing and subsequently deposited CdS nanoparticles on the microsheets by an in-situ hydrothermal method to synthesize the CdS/carbon?CdS/CPC?photocatalyst for photo-driven hydrogen evolution.The carbon microsheets were200 nm thick and 1–20?m wide in dimensions,and CdS nanoparticles with a diameter of20 nm were homogeneously dispersed on the microsheets.The CdS/CPC composites showed a higher visible-light absorption and larger photocurrent density compared with pure CdS.The as-prepared composites exhibited excellent photocatalytic activity for water splitting,and the H2-evolution rate was up to 5367?mol g-1 h-1,approximately 7.8 times that of pure CdS(690?mol h-1 g-1).Moreover,CdS/CPC-2 can retain 93.8%of its original H2-evolution rate after4-cycle continuous catalyzing last for 16 h.The extremely high activity of CdS/CPC can be attributed to its lower interfacial charge-transfer resistance and the effective separation of photogenerated charge carriers.?2?Preparation of CoP/ZIS hybrids and the study of their photocatalytic hydrogen production by water splittingFirstly,ZIS was synthesized by low temperature oil bath method,and ZIS nanosheets were prepared by ultrasonic stripping,next,CoP nanosheets were synthesized by three-step method.And then,a unique 2D-2D architecture nanophotocatalyst was fabricated by combining CoP nanosheets and ZnIn2S4?ZIS?nanosheets through an electrostatic coupling method.Zeta potential,XRD,SEM,TEM,XPS tests proved that the opposite charges on the surface of CoP nanosheets and ZIS nanosheets make them combined tightly.Optical and electrochemical performance test results indicated that the constructed 2D-2D CoP/ZIS nanohybrids could simultaneously facilitate photoelectron transport and suppress charge recombination through their specially coupled heterogeneous interface.As expected,the CoP/ZIS nanohybrids exhibited a remarkably enhanced photocatalytic activity of8775?mol g-1 h-1,which was about 14.7 and 5.7 times higher than bulk ZIS(624?mol g-1 h-1)and ZIS nanosheets(1447?mol g-1 h-1),respectively,and the apparent quantum efficiency?AQE?reached 24.1%?420 nm?.Importantly,the CoP/ZIS nanohybrids showed wonderful stability after a long-time test?24 h,6 cycles?,and96.3%of catalytic activity still remained.Our works show a green and simple way of using bio-waste derived carbon-based materials and highlight their potential application in the field of energy conversion by combining with metal sulfides.Also,a novel electrostatic coupling methold was proposed to advance the development of design 2D-2D layered structure hybrids for large-scale exploration and applications. |
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