RESUMO
Designing a MoS2 catalyst having a large number of active sites and high site activity enables the catalytic activity toward the hydrogen evolution reaction to be improved. Herein, we report the synthesis of a low-cost and catalytically active immobilized single molecular molybdenum disulfide on carbonized polyacrylonitrile (MoS2-cPAN) electrocatalyst. From the extended X-ray absorption fine structure spectra analysis, we found that the as-prepared material has no metal-metal scattering and it resembles MoS2 with a molecular state. Meanwhile, the size of the molecular MoS2 has been estimated to be about 1.31 nm by high-angle annular dark-field scanning transmission electron microscopy. A low coordination number and maximum utilization of the single molecular MoS2 surface enable MoS2-cPAN to demonstrate electrochemical performance significantly better than that of bulk MoS2 by two orders of exchange current density ( jo) and turnover frequency to the hydrogen evolution.
RESUMO
Mucin-producing carcinoma of the gallbladder is rare, and its imaging features have not been well documented. Its symptoms and signs are nonspecific and the prognosis of the disease is poor. We present a 73-year-old male with mucin-producing carcinoma of the gallbladder, emphasizing its imaging features on ultrasound, computed tomography and magnetic resonance imaging. The tumor usually presents as a cauliflower-like soft tissue mass with small calcified spots in the gallbladder wall and some laminated high viscosity fluid inside the gallbladder cavity. Recognition of these features can provide clues to the diagnosis of mucin-producing carcinoma of the gallbladder.
