Taming Electrons in Pt/C Catalysts to Boost the Mesokinetics of Hydrogen Production

Taming the electron transfer across metal–support interfaces appears to be an attractive yet challenging methodology to boost catalytic properties.Herein,we demonstrate a precise engineering strategy for the carbon surface chemistry of Pt/C catalysts—that is,for the electron-withdrawing/donating oxygencontaining groups on the carbon surface—to fine-tune the electrons of the supported metal nanoparticles.Taking the ammonia borane hydrolysis as an example,a combination of density functional theory(DFT)calculations,advanced characterizations,and kinetics and isotopic analyses reveals quantifiable relationships among the carbon surface chemistry,Pt charge state and binding energy,activation entropy/enthalpy,and resultant catalytic activity.After decoupling the influences of other factors,the Pt charge is unprecedentedly identified as an experimentally measurable descriptor of the Pt active site,contributing to a 15-fold increment in the hydrogen generation rate.Further incorporating the Pt charge with the number of Pt active sites,a mesokinetics model is proposed for the first time that can individually quantify the contributions of the electronic and geometric properties to precisely predict the catalytic performance.Our results demonstrate a potentially groundbreaking methodology to design and manipulate metal–carbon catalysts with desirable properties.

A new process to improve short-chain fatty acids and bio-methane generation from waste activated sludge

As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.

Overexpression of Jak1 Activating Mutants in Hepatocytes Is Insufficient to Generate Hepatocellular Carcinoma in Zebrafish

Hepatocellular carcinoma （HCC）, a major subtype of liver cancers, is a prevalent human malignancy worldwide. In men, HCC is the fifth frequently diagnosed cancer but the second most common cause of cancer death. In women, it ranks seventh in cancer diagnosis and sixth in cancer-related death （Jemal et al., 2011）. Unlike some other cancers, such as breast cancer and colon cancer, the molecular etiology of HCC re- mains largely unknown. Infection of hepatitis virus is considered as a major risk factor in the development of liver cancers （Parkin, 2006）. Currently, there are limited options to treat HCC except for chemotherapy. Elucidating molecular mechanism of hepatocyte transformation will help develop new treatments for cancer. The widely accepted multi-step progression of carcinogenesis consists of genetic alterations which regulate cell proliferation, apoptosis and so on （Vogelstein and Kinzler, 1993）. Moreover, abnormal activation of signaling pathways has been proposed as an oncogenic driver for cancer development. For example, Kras activation occurs in 7% of human liver cancer patients. Activated Kras is sufficient to induce robust liver tumorigenesis in transgenic animal models （Nguyen et al., 2011）.