?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F38458%2F&rft.title=Toward+Rational+Design+of+Graphene+Nanomaterials%3A+Manipulating+Chemical+Composition+to+Identify+Governing+Properties+for+Electrochemical+and+Biological+Activities&rft.creator=Wang%2C+Yan&rft.description=The+unique+properties+of+graphene-based+nanomaterials+(GMs)+have+enabled+various+applications+in+the+fields+of+electronics%2C+energy%2C+environment%2C+and+biotechnology.+Yet%2C+their+potential+inherent+hazard+poses+risks+to+human+health+and+the+environment%2C+which+could+be+a+barrier+to+the+success+of+these+applications.+A+critical+underpinning+of+sustainable+material+development+is+rational+design.+This+approach+involves+the+ability+to+control+material+outcomes%2C+requiring+the+establishment+of+property-function+and+property-hazard+relationships.+This+dissertation+aims+to+demonstrate+an+ability+to+rationally+design+GMs+by+manipulating+chemical+composition+and+establishing+the+relationships+that+correlate+material+properties+to+their+electrochemical+activity+(function)+and+bioactivity+(hazard).+The+electrochemical+activity+is+represented+by+the+material+reactivity+for+important+electrochemical+reactions+(oxygen+reduction+reaction%2C+ORR+and+oxygen+evolution+reaction%2C+OER).+The+bioactivity+is+represented+as+the+material+propensity+to+oxidize+a+cellular+biomolecule+(glutathione)+and+inactivate+the+bacteria+(Escherichia+coli).%0D%0A%0D%0AMaterial+sets+of+graphene+oxide+(GO)+and+nitrogen-doped+graphene+(NG)+are+investigated+using+various+complementary+characterization+techniques+to+determine+the+material+properties+that+govern+electrochemical+and+biological+activities+as+chemical+composition+changes.+The+results+suggest+both+activities+are+governed+by+synergistic+effects+from+multiple+properties%2C+including+specific+oxygen+and+nitrogen+sites+and+properties+arising+as+a+consequence+of+changing+chemical+composition.+Enhanced+aqueous+dispersion+and+defect+density+are+important+for+GO+bioactivity.+Additionally%2C+coupled+experimental+and+computational+approaches+elucidate+the+synergistic+role+of+adjacent+epoxide+and+hydroxyl+groups+on+GO+in+directly+oxidizing+glutathione.+As+the+surface+of+GO+is+reduced%2C+the+electrochemical+and+biological+activities+are+governed+by+a+balance+of+carbonyl+groups+and+electrical+conductivity.+For+NG%2C+N-types+control+electrochemical+reactions%2C+ORR+(graphitic-N)+and+OER+(pyridinic-N).+Further%2C+the+predominance+of+graphitic-N+enhances+oxidative+stress-related+bioactivity%2C+which+is+an+important+contribution+since+very+little+is+known+surrounding+NG+bioactivity.%0D%0A%0D%0ACollectively%2C+this+dissertation+supports+the+use+of+chemical+composition+manipulation+to+control+material+properties+and+in+turn%2C+function+and+hazard+outcomes.+The+established+property-function+and+property-hazard+relationships+provide+rational+design+guidance+for+GMs.+The+holistic+approach+herein+is+applicable+to+other+nanomaterials+and+thus%2C+will+continue+to+contribute+to+the+advancement+of+sustainable+nanotechnology.&rft.date=2020-07-31&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F38458%2F1%2Fwangy_etdPitt2020.pdf&rft.identifier=++Wang%2C+Yan++(2020)+Toward+Rational+Design+of+Graphene+Nanomaterials%3A+Manipulating+Chemical+Composition+to+Identify+Governing+Properties+for+Electrochemical+and+Biological+Activities.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++