title: Tailoring Transition-Metal Hydroxides and Oxides by Photon-Induced Reactions.
abstract: Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications, for example as battery electrode materials or electrocatalysts for fuel generation. Here, we report the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. A Nd:YAG laser with wavelengths of 532 nm or 1064 nm was used. The Ni2+, Mn2+, and Co2+ion-containing aqueous solution undergoes photo-induced reactions and produces hollow metal-oxide nanospheres (Ni0.18Mn0.45Co0.37Ox) or core-shell metal hydroxide nanoflowers ([Ni0.15Mn0.15Co0.7(OH)2](NO3)0.2⋅H2O), depending on the laser wavelengths. We propose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures. The study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, USA.
authors.forename: Kai-Yang
authors.identifier: 0000-0003-3289-1322
authors.initials: KY
authors.lastname: Niu
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, USA.|State Key Laboratory of Mechanical Transmission, College of Physics, Chongqing University, Chongqing, 400044, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Ye
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Nordlund
authors.affiliation: Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, USA.
authors.forename: Marca M
authors.initials: MM
authors.lastname: Doeff
authors.affiliation: Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, USA.|Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, USA. hmzheng@lbl.gov.|Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. hmzheng@lbl.gov.
authors.forename: Haimei
authors.initials: H
authors.lastname: Zheng
keywords: nanostructures; photochemistry; reaction pathways; transition-metal hydroxides; vibrational excitation