科学家们发明了一种新型太阳能电池板，可以帮助降低可持续使用氢气的成本
新的太阳能电池板在将水转化为氢气和氧气方面达到了9%的效率——模仿了自然光合作用中的一个关键步骤
密歇根大学电气与计算机工程教授Zetian Mi说：“最终，我们相信人工光合作用设备将比自然光合作用更有效，这将为实现碳中和提供一条途径”
中国石化新闻网讯 据油价网报道，美国密歇根大学的科学家们开发了一种新型太阳能电池板，将水转化为氢气和氧气的效率达到9%，模仿了自然光合作用的关键步骤。在户外，它代表了技术上的重大飞跃，比同类太阳能水分解实验效率高出近10倍。
但最大的好处是降低了可持续氢气的成本。这是通过缩小半导体来实现的，半导体通常是设备中最昂贵的部分。密歇根大学科学家团队的自我修复的半导体可以承受相当于160个太阳的聚光。
目前，人类主要从化石燃料甲烷中生产氢气，在这个过程中使用了大量的化石能源。然而，植物利用阳光从水中获取氢原子。随着人类试图减少碳排放，氢气作为一种独立的燃料，以及由回收的二氧化碳制成的可持续燃料的组成部分，都具有吸引力。同样，许多化学过程也需要它，例如生产化肥。
密歇根大学电气与计算机工程教授Zetian Mi领导了这项研究，研究结果发表在《自然》杂志上。Zetian Mi说：“最终，我们相信人工光合作用设备将比自然光合作用更有效，这将为实现碳中和提供一条途径。”
这一突出成果来自两个方面的进展。
第一个是在不破坏利用光的半导体的情况下集中太阳光的能力。密歇根大学电气和计算机工程研究员、该研究的第一作者Peng Zhou说：“与一些只在低光强度下工作的半导体相比，我们将半导体的尺寸减小为不到原来的百分之一。用我们的技术生产氢气可能会非常便宜。”
第二种方法是利用太阳光谱中能量较高的部分来分解水，同时利用光谱中能量较低的部分来提供热量来促进反应。这种魔力是由一种半导体催化剂实现的，这种催化剂在利用阳光驱动化学反应时，会随着使用而自我改善，抵抗这种催化剂通常会经历的退化。
除了处理高光强度外，它还可以在对计算机半导体不利的高温下茁壮成长。高温加速了水的分解过程，额外的热量也促使氢气和氧气保持分离，而不是重新结合并再次形成水。这两种方法都帮助研究小组收获了更多的氢气。
在户外实验中，Peng Zhou教授设置了一个房屋窗户大小的透镜，将阳光聚焦到只有几英寸宽的实验面板上。在这个面板中，半导体催化剂被一层水覆盖着，它分离出的氢气和氧气不断起泡。
催化剂由氮化铟镓纳米结构制成，生长在硅表面。半导体晶片捕获光线，将其转化为自由电子和小孔——电子被光线释放后留下的带正电的空隙。纳米结构中布满了直径为1/2000毫米的纳米级金属球，利用这些电子和小孔来帮助引导反应。
面板上的一层简单的绝缘层将温度保持在75摄氏度(167华氏度)，这个温度足够促进反应，同时也足够凉爽以使半导体催化剂发挥良好作用。室外版本的实验，在阳光和温度不太可靠的情况下，将太阳能转化为氢燃料的效率达到6.1%。然而，在室内，该系统达到了9%的效率。
密歇根大学科学家团队打算解决的下一个挑战是进一步提高效率，并实现可以直接输入燃料电池的超高纯度氢气。
与这项工作相关的一些知识产权已被授权给NS纳米技术公司和NX燃料公司，这两家公司都是由Zetian Mi共同创立的。
这是很大的进步。9%的效率可能是一个新的纪录。剩下的问题是成本问题。无论经济如何发展，这加上一种超级经济的氮肥形成手段将对世界经济作出巨大贡献。这将节省试图储存氢气的成本，从而简化了快速采用。
李峻 编译自 油价网
原文如下：
Scientists Make Major Breakthrough In Sustainable Hydrogen Production
· Scientists have created a new type of solar panel that could help drive down the cost of sustainable hydrogen.
· The new solar panel achieved 9% efficiency in converting water into hydrogen and oxygen – mimicking a crucial step in natural photosynthesis.
· Zetian Mi, U-M professor of electrical and computer engineering, said, “In the end, we believe that artificial photosynthesis devices will be much more efficient than natural photosynthesis, which will provide a path toward carbon neutrality.”
University of Michigan scientists developed a new kind of solar panel achieving 9% efficiency in converting water into hydrogen and oxygen – mimicking a crucial step in natural photosynthesis. Outdoors, it represents a major leap in the technology, nearly 10 times more efficient than solar water-splitting experiments of its kind.
But the biggest benefit is driving down the cost of sustainable hydrogen. This is enabled by shrinking the semiconductor, typically the most expensive part of the device. The team’s self-healing semiconductor withstands concentrated light equivalent to 160 suns.
Currently, humans primarily produce hydrogen from the fossil fuel methane, using a great deal of fossil energy in the process. However, plants harvest hydrogen atoms from water using sunlight. As humanity tries to reduce its carbon emissions, hydrogen is attractive as both a standalone fuel and as a component in sustainable fuels made with recycled carbon dioxide. Likewise, it is needed for many chemical processes, producing fertilizers for instance.
Zetian Mi, U-M professor of electrical and computer engineering led the study as reported in the journal in Nature. Mi said, “In the end, we believe that artificial photosynthesis devices will be much more efficient than natural photosynthesis, which will provide a path toward carbon neutrality.”
The outstanding result comes from two advances.
The first is the ability to concentrate the sunlight without destroying the semiconductor that harnesses the light.
Peng Zhou, U-M research fellow in electrical and computer engineering and first author of the study said, “We reduced the size of the semiconductor by more than 100 times compared to some semiconductors>The second is using both the higher energy part of the solar spectrum to split water and the lower part of the spectrum to provide heat that encourages the reaction. The magic is enabled by a semiconductor catalyst that improves itself with use, resisting the degradation that such catalysts usually experience when they harness sunlight to drive chemical reactions.
In addition to handling high light intensities, it can thrive in high temperatures that are punishing to computer semiconductors. Higher temperatures speed up the water splitting process, and the extra heat also encourages the hydrogen and oxygen to remain separate rather than renewing their bonds and forming water>For the outdoor experiment, Zhou set up a lens about the size of a house window to focus sunlight>The catalyst is made of indium gallium nitride nanostructures, grown>A simple insulating layer atop the panel keeps the temperature at a toasty 75° Celsius, or 167° Fahrenheit, warm enough to help encourage the reaction while also being cool enough for the semiconductor catalyst to perform well. The outdoor version of the experiment, with less reliable sunlight and temperature, achieved 6.1% efficiency at turning the energy from the sun into hydrogen fuel. However, indoors, the system achieved 9% efficiency.
The next challenges the team intends to tackle are to further improve the efficiency and to achieve ultrahigh purity hydrogen that can be directly fed into fuel cells.
Some of the intellectual property related to this work has been licensed to NS Nanotech Inc. and NX Fuels Inc., which were co-founded by Mi. The University of Michigan and Mi have a financial interest in both companies.
This is quite the improvement! 9% efficiency might be a new record. What is left to answer would be the costs.
However the economics work out, this plus a super economical means to form up nitrogen fertilizer would be a huge contribution to the world economy. That would save the cost of trying to store the hydrogen thus simplify rapid adoption.
