/**
 * @param string|null $name
 * @return array|null
 */
function splitName($name)
{
    if (empty($name) || empty(trim($name))) {
        return null;
    }
    //该正则是用来提取$name参数里面的中文字符的。
    preg_match_all('/[\x{4e00}-\x{9fff}]+/u', $name, $matchers);
    $matchersCount = isset($matchers[0]) ? count($matchers[0]) : 0;
    if ($matchersCount <= 0) {
        return null;
    }
    $firstName = $lastName = '';
    if ($matchersCount == 1) {
        $lastName = mb_substr($name, 0, 1);
        $firstName = mb_substr($name, 1);
    } else {
        foreach ($matchers[0] as $index => $value) {
            if ($index == 0) {
                $firstName = $value;
            } else {
                $lastName .= $value;
            }
        }
    }
    return compact('firstName', 'lastName');
}


var_dump(splitName("姓名"));
var_dump(splitName("姓1231名adsa"));
var_dump(splitName("买买提·吐尔逊"));

测试结果如下：