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Title: Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings

Abstract

Sunlight drives photosynthesis and associated biological processes, and also influences inorganic processes that shape Earth’s climate and geochemistry. Bacterial solar-to-chemical energy conversion on this planet evolved to use an intricate intracellular process of phototrophy. However, a natural nonbiological counterpart to phototrophy has yet to be recognized. In this work, we reveal the inherent “phototrophic-like” behavior of vast expanses of natural rock/soil surfaces from deserts, red soils and karst environments, all of which can drive photon-to-electron conversions. Using scanning electron microscopy, transmission electron microscopy, micro-Raman spectroscopy and X-ray absorption spectroscopy, Fe and Mn (oxyhydr)oxide-rich coatings were found in rock varnishes, as were Fe (oxyhydr)oxides on red soil surfaces and minute amounts of Mn oxides on karst rock surfaces. By directly fabricating a photoelectric detection device on the thin section of a rock varnish sample, we have recorded the first in situ photocurrent micromapping of the coatings, which behave as highly sensitive and stable photoelectric systems. Additional measurements of red soil and powder separated from the outermost surface of karst rocks yielded photocurrents that are also sensitive to irradiation. The prominent solar-responsive capability of the phototrophic-like rocks/soils is ascribed to the semiconducting Fe and Mn (oxyhydr)oxide mineral coatings. The native semiconducting Fe/Mn-richmore » coatings may play a role similar in part to photosynthetic systems and thus provide a distinctive driving force for redox (bio)geochemistry on Earth’s surfaces.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [3];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [4];  [1] more »;  [5] « less
  1. Peking University
  2. Canadian Light Source, Inc. Saskatoon, SK Canada
  3. Chinese Academy of Sciences
  4. Central South University
  5. Virginia Polytechnic Institute
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1530846
Report Number(s):
PNNL-SA-142289
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 116; Journal Issue: 20
Country of Publication:
United States
Language:
English

Citation Formats

Lu, Anhuai, Li, Yan, Ding, Hongrui, Xu, Xiaoming, Li, Yanzhang, Ren, Guiping, Liang, Jing, Liu, Yuwei, Hong, Hao, Chen, Ning, Chu, Shengqi, Liu, Feifei, Li, Yan, Wang, Haoran, Ding, Cong, Wang, Changqiu, Lai, Yong, Liu, Juan, Dick, Jeffrey, Liu, Kaihui, and Hochella, Michael F. Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings. United States: N. p., 2019. Web. doi:10.1073/pnas.1902473116.
Lu, Anhuai, Li, Yan, Ding, Hongrui, Xu, Xiaoming, Li, Yanzhang, Ren, Guiping, Liang, Jing, Liu, Yuwei, Hong, Hao, Chen, Ning, Chu, Shengqi, Liu, Feifei, Li, Yan, Wang, Haoran, Ding, Cong, Wang, Changqiu, Lai, Yong, Liu, Juan, Dick, Jeffrey, Liu, Kaihui, & Hochella, Michael F. Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings. United States. doi:10.1073/pnas.1902473116.
Lu, Anhuai, Li, Yan, Ding, Hongrui, Xu, Xiaoming, Li, Yanzhang, Ren, Guiping, Liang, Jing, Liu, Yuwei, Hong, Hao, Chen, Ning, Chu, Shengqi, Liu, Feifei, Li, Yan, Wang, Haoran, Ding, Cong, Wang, Changqiu, Lai, Yong, Liu, Juan, Dick, Jeffrey, Liu, Kaihui, and Hochella, Michael F. Tue . "Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings". United States. doi:10.1073/pnas.1902473116.
@article{osti_1530846,
title = {Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings},
author = {Lu, Anhuai and Li, Yan and Ding, Hongrui and Xu, Xiaoming and Li, Yanzhang and Ren, Guiping and Liang, Jing and Liu, Yuwei and Hong, Hao and Chen, Ning and Chu, Shengqi and Liu, Feifei and Li, Yan and Wang, Haoran and Ding, Cong and Wang, Changqiu and Lai, Yong and Liu, Juan and Dick, Jeffrey and Liu, Kaihui and Hochella, Michael F.},
abstractNote = {Sunlight drives photosynthesis and associated biological processes, and also influences inorganic processes that shape Earth’s climate and geochemistry. Bacterial solar-to-chemical energy conversion on this planet evolved to use an intricate intracellular process of phototrophy. However, a natural nonbiological counterpart to phototrophy has yet to be recognized. In this work, we reveal the inherent “phototrophic-like” behavior of vast expanses of natural rock/soil surfaces from deserts, red soils and karst environments, all of which can drive photon-to-electron conversions. Using scanning electron microscopy, transmission electron microscopy, micro-Raman spectroscopy and X-ray absorption spectroscopy, Fe and Mn (oxyhydr)oxide-rich coatings were found in rock varnishes, as were Fe (oxyhydr)oxides on red soil surfaces and minute amounts of Mn oxides on karst rock surfaces. By directly fabricating a photoelectric detection device on the thin section of a rock varnish sample, we have recorded the first in situ photocurrent micromapping of the coatings, which behave as highly sensitive and stable photoelectric systems. Additional measurements of red soil and powder separated from the outermost surface of karst rocks yielded photocurrents that are also sensitive to irradiation. The prominent solar-responsive capability of the phototrophic-like rocks/soils is ascribed to the semiconducting Fe and Mn (oxyhydr)oxide mineral coatings. The native semiconducting Fe/Mn-rich coatings may play a role similar in part to photosynthetic systems and thus provide a distinctive driving force for redox (bio)geochemistry on Earth’s surfaces.},
doi = {10.1073/pnas.1902473116},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 20,
volume = 116,
place = {United States},
year = {2019},
month = {5}
}