Synthesis and Characterization of Nontoxic Hollow Iron Oxide (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2552099pt" id="M1" height="8.2614pt" version="1.1" viewBox="-0.0657574 -8.00619 10.1905 8.2614" width="10.1905pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g5-223" d="M563 442L553 454L479 439C463 404 440 354 416 322H414C389 422 344 454 283 454C151 454 21 310 21 162C21 48 73 -12 135 -12C182 -12 249 19 325 126H327C339 20 368 -12 407 -12C452 -12 507 21 557 110L530 136C508 107 493 92 480 92C462 92 453 123 430 253C459 292 528 386 563 442ZM318 186C290 133 235 76 202 76C175 76 154 108 154 184C154 275 198 406 247 406C288 406 313 294 318 186Z"/></g></svg>-<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-4.2538pt" id="M2" height="15.791pt" version="1.1" viewBox="-0.0657574 -11.5372 43.6428 15.791" width="43.6428pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g13-68" d="M524 497C519 556 514 633 513 650H40V615C113 608 122 601 122 511V142C122 48 113 42 40 35V0H351V35C264 42 256 48 256 142V300H338C427 300 437 292 448 224H484V423H448C437 359 427 350 338 350H256V571C256 604 260 606 295 606H345C401 606 428 599 449 577C466 559 479 529 489 491L524 497Z"/></g><g transform="matrix(.017,0,0,-0.017,9.214,0)"><path id="g13-99" d="M400 123C365 93 327 80 288 80C216 80 157 134 153 241C251 245 374 254 392 257C414 260 420 273 421 293C421 375 351 454 258 454H257C203 454 148 427 104 383C62 341 30 278 30 202C30 87 103 -12 237 -12C279 -12 357 8 417 99L400 123ZM237 414C276 414 299 362 298 311C298 294 292 291 277 291C236 290 199 289 157 288C164 367 198 414 237 414Z"/></g><g transform="matrix(.012,0,0,-0.012,16.713,4.134)"><path id="g22-48" d="M440 180C404 113 397 110 338 110H183L298 220C398 316 438 379 438 456C438 568 354 635 254 635C192 635 138 610 101 572L36 479L69 452C103 500 144 541 204 541C270 541 306 494 306 425C306 350 267 276 197 193C148 136 89 81 36 30V0H440C451 42 463 106 480 167L440 180Z"/></g><g transform="matrix(.017,0,0,-0.017,23.483,0)"><path id="g13-77" d="M394 664C165 664 42 495 42 323C42 132 181 -15 381 -15C570 -15 725 116 725 332C725 529 576 664 394 664ZM374 622C491 622 571 503 571 304C571 120 494 27 399 27C271 27 196 171 196 343C196 516 274 622 374 622Z"/></g><g transform="matrix(.012,0,0,-0.012,36.627,4.134)"><path id="g22-49" d="M310 382C345 404 366 417 384 433C404 450 417 474 417 501C417 578 357 635 252 635H251C184 635 135 603 107 572L57 506L86 478C122 527 156 554 205 554C250 554 290 528 290 467S227 367 144 340L151 300C168 304 190 308 208 308C260 308 327 275 327 181C327 89 288 49 238 49C177 49 131 93 109 111C95 122 82 119 70 110C57 100 40 82 40 63C40 48 48 34 65 21C86 4 126 -12 177 -12C240 -12 460 60 460 222C460 298 409 363 310 380V382Z"/></g></svg>) Nanoparticles Using a Simple Hydrothermal Strategy

<div>TEM images showing the hollow core and shell of calcinated <i>α</i>-Fe<sub>2</sub>O<sub>3</sub> at (a) 12 h and (b) 24 h.</div>

Journal of Nanomaterials

fig4

Figure 4

Figure 4: Synthesis and Characterization of Nontoxic Hollow Iron Oxide (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2552099pt" id="M1" height="8.2614pt" version="1.1" viewBox="-0.0657574 -8.00619 10.1905 8.2614" width="10.1905pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g5-223" d="M563 442L553 454L479 439C463 404 440 354 416 322H414C389 422 344 454 283 454C151 454 21 310 21 162C21 48 73 -12 135 -12C182 -12 249 19 325 126H327C339 20 368 -12 407 -12C452 -12 507 21 557 110L530 136C508 107 493 92 480 92C462 92 453 123 430 253C459 292 528 386 563 442ZM318 186C290 133 235 76 202 76C175 76 154 108 154 184C154 275 198 406 247 406C288 406 313 294 318 186Z"/></g></svg>-<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-4.2538pt" id="M2" height="15.791pt" version="1.1" viewBox="-0.0657574 -11.5372 43.6428 15.791" width="43.6428pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g13-68" d="M524 497C519 556 514 633 513 650H40V615C113 608 122 601 122 511V142C122 48 113 42 40 35V0H351V35C264 42 256 48 256 142V300H338C427 300 437 292 448 224H484V423H448C437 359 427 350 338 350H256V571C256 604 260 606 295 606H345C401 606 428 599 449 577C466 559 479 529 489 491L524 497Z"/></g><g transform="matrix(.017,0,0,-0.017,9.214,0)"><path id="g13-99" d="M400 123C365 93 327 80 288 80C216 80 157 134 153 241C251 245 374 254 392 257C414 260 420 273 421 293C421 375 351 454 258 454H257C203 454 148 427 104 383C62 341 30 278 30 202C30 87 103 -12 237 -12C279 -12 357 8 417 99L400 123ZM237 414C276 414 299 362 298 311C298 294 292 291 277 291C236 290 199 289 157 288C164 367 198 414 237 414Z"/></g><g transform="matrix(.012,0,0,-0.012,16.713,4.134)"><path id="g22-48" d="M440 180C404 113 397 110 338 110H183L298 220C398 316 438 379 438 456C438 568 354 635 254 635C192 635 138 610 101 572L36 479L69 452C103 500 144 541 204 541C270 541 306 494 306 425C306 350 267 276 197 193C148 136 89 81 36 30V0H440C451 42 463 106 480 167L440 180Z"/></g><g transform="matrix(.017,0,0,-0.017,23.483,0)"><path id="g13-77" d="M394 664C165 664 42 495 42 323C42 132 181 -15 381 -15C570 -15 725 116 725 332C725 529 576 664 394 664ZM374 622C491 622 571 503 571 304C571 120 494 27 399 27C271 27 196 171 196 343C196 516 274 622 374 622Z"/></g><g transform="matrix(.012,0,0,-0.012,36.627,4.134)"><path id="g22-49" d="M310 382C345 404 366 417 384 433C404 450 417 474 417 501C417 578 357 635 252 635H251C184 635 135 603 107 572L57 506L86 478C122 527 156 554 205 554C250 554 290 528 290 467S227 367 144 340L151 300C168 304 190 308 208 308C260 308 327 275 327 181C327 89 288 49 238 49C177 49 131 93 109 111C95 122 82 119 70 110C57 100 40 82 40 63C40 48 48 34 65 21C86 4 126 -12 177 -12C240 -12 460 60 460 222C460 298 409 363 310 380V382Z"/></g></svg>) Nanoparticles Using a Simple Hydrothermal Strategy 

Journal of Nanomaterials

Synthesis and Characterization of Nontoxic Hollow Iron Oxide (-) Nanoparticles Using a Simple Hydrothermal Strategy

Figure 4