金奈米顆粒/三元硫化鎘鋅奈米線之異質結構增益光催化產氫應用之研究

Enhanced Photocatalytic Hydrogen Production with Au Nanoparticles / ZnxCd1-xS Nanowires

陳昱誠(Yu-Cheng Chen)

指導教授 ： 陳力俊

國立清華大學/工學院/材料科學工程學系/碩士(2019年)

摘要

隨著能源的耗竭與環保意識的高漲，作為一種乾淨且可再生的能源，以及近幾十年來的發展，氫能源已被視為解決全球能源危機的主要能源之一，而氫能源的發展已成為全球矚目的焦點。
在本論文中，利用了金奈米顆粒/三元硫化鎘鋅奈米線之組合可以形成優異的光催化產氫性能，並證實了不同化學組成比例的三元硫化鎘鋅奈米線將會具有不同特性的產氫效率表現。在模擬太陽光下（使用AM1.5G的濾光片），硫化鎘鋅奈米線之光催化劑對於產氫的催化活性比純硫化鋅和硫化鎘奈米線高。當鋅與鎘含量的比例接近1:1時，此時樣品的最高的產氫率為57.07 mmol·h-1·g-1，超過純硫化鎘和硫化鋅樣品的各3倍與50倍以上。這種高效的光催化產氫之活性主要歸因於適當的能隙大小和合適的導帶邊緣電位。
此外，以電漿體作為媒介的光催化反應可以增強光激發並改善半導體光催化劑系統中的電荷分離。利用金奈米顆粒附著在不同化學組成比例之硫化鎘鋅奈米線上，在可見或近紅外波長處具有局部表面電漿共振效應產生。在此研究中通過電子束熱蒸鍍沉積2.5-, 3.5-, 5- 和10奈米的金薄膜於三元硫化鎘鋅奈米線上然後再進行熱退火處理形成金奈米顆粒/奈米線異質結構。發現產氫效率最高的異質結構是鍍上3.5奈米的金隨後進行退火處理而形成。當在模擬太陽光之情況下，適當大小的金奈米顆粒以及平均的金奈米顆粒局部分佈可以使金-硫化鎘鋅奈米之異質結構的產氫效率表現再提升至將近1.7倍。

關鍵字

產氫 ； 光催化 ； 硫化鎘鋅奈米線 ； 金奈米顆粒 ； 電漿子性質

並列摘要

The production of hydrogen energy, a clean and renewable energy source, has been one of the prominent subjects in recent decades as a result of the global fossil energy shortage as well as environmental degradation crisis. In most reports on hydrogen production, photocatalysts play the key role to enhance the production rate.
In this thesis, excellent photocatalytic properties for hydrogen production with Au nanoparticles (NPs) / ternary zinc cadmium sulfide (ZnxCd1-xS) nanowires (NWs) have been demonstrated. The ZnxCd1-xS NWs photocatalyst shows much higher catalytic activity for H2-production than ZnS and CdS NWs under simulated solar light (with AM1.5G filter). When the x ratio of Zn approaches 0.5, the Zn0.5Cd0.5S sample exhibits the highest H2-production rate, exceeding that of the pure CdS and ZnS samples by more than 3 times and 50 times, respectively, by using 1.4 M Na2S and 1.0 M Na2SO3 as sacrificial reagents in water under a 300 W xenon arc lamp. This high photocatalytic H2-production activity is attributed predominantly to appropriate band gap width and suitable conduction band edge potential of the ZnxCd1-xS NWs.
Additionally, plasmon-mediated photocatalysis may enhance photoexcitation and improve charge separation in semiconductor photocatalyst system. The ZnxCd1-xS NWs attached with Au NPs exhibit localized surface plasmon resonance (LSPR) at visible or near-infrared wavelengths to enhance the hydrogen production.
The NPs/NWs heterostructure were formed by depositing 2.5-, 3.5-, 5- and 10-nm gold films using electron bean evaporation followed by annealing. The H2-production efficiency of the heterogeneous structure with 3.5 nm Au film was found to be the highest. Under simulated solar light, appropriate Au NPs size and distribution can increase H2-production rate by nearly 1.7 times with Au NPs / Zn0.5Cd0.5S NWs heterostructure. The efficiency of H2-production of the ZnxCd1-xS NWs with Au NPs was significantly improved by the localized surface plasmon resonance effect.

並列關鍵字

Hydrogen production ； Photocatalytic ； ZnxCd1-xS nanowires ； Au nanoparticles ； Plasmonic properties

參考文獻

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