Large-Scale and Controllable Synthesis of Graphene Quantum Dots from Rice Husk Biomass: A Comprehensive Utilization Strategy

Abstract

In this work, rice husk biomass was utilized as an abundant source to controllably prepare high-quality graphene quantum dots (GQDs) with a yield of ca. 15 wt %. The size, morphology, and structure of the rice-husk-derived GQDs were determined by high-resolution transmission electron microscopy, atomic force microscopy, and Raman spectroscopy. The as-fabricated GQDs can be stably dispersed in water, exhibiting bright and tunable photoluminescence. A cell viability test further confirmed that the GQDs possess excellent biocompatibility, and they can be easily adopted for cell imaging via a facile translocation into the cytoplasm. It is worth noting that mesoporous silica nanoparticles were also synthesized as a byproduct during the fabrication of GQDs. As such, our strategy achieves a comprehensive utilization of rice husks, exhibiting tremendous benefits on both the economy and environment.

Biomass‐Derived Carbon Dots and Their Applications

“…HTC is a carbon nanomaterial synthesis technology, which has been widely used in many fields . HTC has been used to prepare novel carbon‐based materials from biomass carbon precursors such as sweet pepper, garlic, husks of nuts, papaya juice, rice husk, and other biomass materials …”

“…With biomass as the carbon source, the particle size of BCDs prepared by pyrolysis is generally between 0.4 and 6 nm, and the quantum yield is between 3% and 25%. In plants, BCDs are prepared by pyrolysis methods, such as rice husks, plant leaves, grass, and gynostemma . BCDs were prepared by pyrolysis using rice husk biomass as a carbon source.…”

“…In recent years, various biomass has been used as carbon sources to prepare BCDs ( Figure ). The biomass used includes walnut peel, garlic, papaya juice, rice husk, winter melon, lychee seeds, goose feather, silkworm chrysalis, bee pollen, milk, Phyllanthus acidus, and baked lamb . BCDs prepared using biomass have been applied to biological imaging, sensors, drug delivery, and other applications ( Scheme ).…”

Molecular imaging with nanoparticles: the dwarf actors revisited 10 years later

“…To give a taste of the luxurious proliferation of potential raw materials used to create carbon dots we append here an incomplete list, it includes: soot (Allam and Sarkar 2011; Liu et al 2007; Vinci and Colón 2012; Baker and Colón 2009), carbon nanotubes (Bottini et al 2006; Zhou et al 2007), carbon fibers (Vinci et al 2015), graphene sheets (Pan et al 2010), activated carbon (Qiao et al 2010; Li et al 2011b; Dong et al 2010), graphite (Sun et al 2006; Hu et al 2009; Cao et al 2007; Zhao et al 2008; Lu et al 2009; Zheng et al 2009, 2011; Wang et al 2011) various small organic molecules (Zheng et al 2015) such as acetic acid (Fang et al 2011), amino acids (Wei et al 2014), citric acid or glucose (Dong et al 2012a, b), sucrose (Zhang et al 2010), carbohydrates (Liu et al 2011a, b; Peng and Travas-Sejdic 2009), C 60 molecules (Lu et al 2011), and nanodiamonds (Yu et al 2005a, b; Chang et al 2008; Wolfbeis 2015). Research on these eco-friendly nanoparticles blossomed from 2014 onwards, extending the syntheses to a further wide range of natural raw-stuffs and ecologically friendly syntheses including: wool (Wang et al 2016a), flour (Zhang et al 2015), bagasse (Du et al 2014), radishes (Liu et al 2017a), orange juice (Sahu et al 2012), peaches (Atchudan et al 2016), coffee grounds (Hsu et al 2012), garlic (Sun et al 2016), coriander (Sachdev and Gopinath 2015), papaya (Wang et al 2016a, b, c, d), carrots (Liu et al 2017b), potatoes (Shen et al 2017), waste frying oil (Hu et al 2014), waste biomass (Suryawanshi et al 2014) and pigeon feathers, eggs and manure (Ye et al 2017); the list becomes longer almost every day. The number of protocols reported for preparation of carbon dots is almost equally long, see below.…”

Niobium-oxygen octahedra and oxygen interstitial defect emissions in calcium niobate matrix and its color manipulation via doping Pr3+

“…Because of the practical applications in human daily life, luminescent materials show a very important and special status, and have attracted much attention. [1][2][3] The research of luminescent materials is multidisciplinary, including physics, chemistry, materials science, biomedicine, and device technology. In addition to the existing basic applications in daily life, it could always bring novel concepts and exciting application prospects in both of the traditional and rising fields, such as three dimensional and flexible displays, cell imaging and tracking, and cancer therapy.…”