科学家复制出光合作用
[color=blue]An international team of researchers led by Monash University has used chemicals found in plants to replicate a key process in photosynthesis paving the way to a new approach that uses sunlight to split water into hydrogen and oxygen[/color].The breakthrough could revolutionise the renewable energy industry by making hydrogen – touted as the clean, green fuel of the future – cheaper and easier to produce on a commercial scale.
Professor Leone Spiccia, Mr Robin Brimblecombe and Dr Annette Koo from Monash University teamed with Dr Gerhard Swiegers at the CSIRO and Professor Charles Dismukes at Princeton University to develop a system comprising a coating that can be impregnated with a form of manganese, a chemical essential to sustaining photosynthesis in plant life.
"We have copied nature, taking the elements and mechanisms found in plant life that have evolved over 3 billion years and recreated one of those processes in the laboratory," Professor Spiccia said.
"A manganese cluster is central to a plant's ability to use water, carbon dioxide and sunlight to make carbohydrates and oxygen. Man-made mimics of this cluster were developed by Professor Charles Dismukes some time ago, and we've taken it a step further, harnessing the ability of these molecules to convert water into its component elements, oxygen and hydrogen," Professor Spiccia said.
"The breakthrough came when we coated a proton conductor, called Nafion, onto an anode to form a polymer membrane just a few micrometres thick, which acts as a host for the manganese clusters."
"Normally insoluble in water, when we bound the catalyst within the pores of the Nafion membrane, it was stabilised against decomposition and, importantly, water could reach the catalyst where it was oxidised on exposure to light."
This process of "oxidizing" water generates protons and electrons, which can be converted into hydrogen gas instead of carbohydrates as in plants.
"Whilst man has been able to split water into hydrogen and oxygen for years, we have been able to do the same thing for the first time using just sunlight, an electrical potential of 1.2 volts and the very chemical that nature has selected for this purpose," Professor Spiccia said.
Testing revealed the catalyst assembly was still active after three days of continuous use, producing oxygen and hydrogen gas in the presence of water, an electrical potential and visible light.
Professor Spiccia said the efficiency of the system needed to be improved, but this breakthrough had huge potential. "We need to continue to learn from nature so that we can better master this process."
"Hydrogen has long been considered the ideal clean green fuel, energy-rich and carbon-neutral. The production of hydrogen using nothing but water and sunlight offers the possibility of an abundant, renewable, green source of energy for the future for communities across the world."
The research is published in August in the scientific journal Angewandte Chemie, International Edition.
[url=http://www.sciencedaily.com/images/2008/08/080817223544-large.jpg][img=300,391]http://www.sciencedaily.com/images/2008/08/080817223544.jpg[/img][/url]
[i]Scientists have developed a way to use chemicals found in plants to replicate a key process in photosynthesis. (Credit: iStockphoto/Dane Steffes)[/i]
[b]Journal reference[/b]:
Robin Brimblecombe, Gerhard F. Swiegers, G. Charles Dismukes, Leone Spiccia. [b]Sustained Water Oxidation Photocatalysis by a Bioinspired Manganese Cluster[/b]. [i]Angewandte Chemie[/i], Published Online: Aug 1 2008 DOI: [url=http://dx.doi.org/10.1002/anie.200801132][color=#0000ff]10.1002/anie.200801132[/color][/url]
Aug 18, 2008
Monash University [table=98%,#f8f9f4][tr][td]论文作者：Leone Spiccia 期刊：《应用化学》 发布时间：2008-8-19 10:55:41
[/td][/tr][tr][td][align=left][table=98%][tr][td][/td][/tr][tr][td][/td][/tr][tr][td]科学家复制出光合作用过程[/td][/tr][tr][td][/td][/tr][/table]
[align=center][img]http://www.sciencenet.cn/paper/upload/20088191357715.jpg[/img][/align][align=center][font=楷体_GB2312]图片来源：iStockphoto/Dane Steffes[/font][/align]据美国每日科学网报道，由澳大利亚莫纳什大学领导的一支国际科学家小组利用在植物中发现的化学物质来复制光合作用的关键过程，为利用阳光将水分解成氢和氧开辟了一条新途径。此技术性突破可以革新再生能源行业的制氢工艺，从而可以利用阳光来大规模生产清洁的绿色能源――氢气。
植物在光合作用过程中，可利用太阳光将水分解为活泼的氢和氧，再利用活泼氢同二氧化碳作用合成有机物。莫纳什大学的利昂·斯皮西亚教授、罗宾·布里姆布来可比先生和安妮特·可罗和澳大利亚联邦科学与工业研究组织（CSIRO）的格哈德·斯伟格斯以及美国普林斯顿大学的查尔斯·迪斯莫克斯共同开发了一个系统，此系统由一层涂层组成，里面可以注入锰，而锰是维持植物光合作用的基本化学物质。
斯皮西亚教授说：“我们已经复制出了自然的光合作用过程，采用植物进化了30亿年的光合作用的化学物质和机理，在实验室再造了这些过程之一。锰簇是植物利用水、二氧化碳和阳光制造碳水化合物和氧气的中心枢纽。查尔斯·迪斯莫克斯不久前已经开发出这种人造锰簇，我们将它发扬光大，利用这些分子的能力将水分解成氢和氧。当我们将一层质子导体――Nafion薄膜覆盖在一个电极上形成一层仅几微米厚的聚合体膜时，此技术突破出现了。这层聚合体膜充当锰簇的载体。锰在正常情况下不溶解于水，但可以和Nafion薄膜小孔中的催化剂结合，形成不易分解的稳定结构，当水到达此催化剂时，在阳光的照射下就会发生氧化反应。”
这一产生质子和电子的“氧化”水的过程可以将水变成氢气而不是植物所产生的碳水化合物。斯皮西亚教授说：“人类利用化学过程将水分解成氢和氧已经有很多年了，但我们首次利用阳光来做同样的事情。”
初步测试表明此催化剂连续使用3天之后还有活性，由此分解出来的氢气和氧气可以在燃料电池中结合成水，产生电力供住宅和电动车全天24小时使用，且不排放碳而是排放水。斯皮西亚教授表示此系统的效率还有待提高，但这一技术突破具有巨大的潜在价值。“我们需要不断地从自然界中学习，因此我们能使这一过程更加高明。氢气被认为是理想的清洁绿色能源，能效高且没有碳排放。而此过程生产氢气只需水和阳光，就能源源不断地提供大量的绿色能源，供未来社会使用。”
此研究成果发表在8月刊的科学杂志德国《应用化学》（[i]Angewandte Chemie International Edition[/i]）上。（来源：网易探索 尼特） （《应用化学》（[i]Angewandte Chemie International Edition[/i]），doi：10.1002/anie.200801132，Robin Brimblecombe，Leone Spiccia） [b]更多阅读（英文）[/b] [url=http://www3.interscience.wiley.com/journal/121359451/abstract?CRETRY=1&SRETRY=0][color=#800000]《应用化学》发表论文摘要[/color][/url]
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